Turquoise
Turquoise pebble, one inch (2. 5 cm) long. This pebble is greenish and therefore low grade
General
Category	Mineral
Chemical formula	CuAl6(PO4)4(OH)8·4H2O
Identification
Color	Blue, blue-green, green
Crystal habit	Massive, nodular
Crystal system	Triclinic
Cleavage	Good to perfect - usually N/A
Fracture	Conchoidal
Mohs Scale hardness	5-6
Luster	Waxy to subvitreous
Refractive index	1. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes In Mineralogy, shape and size give rise to descriptive terms applied to the typical appearance or habit of Crystals The many terms used by mineralogists A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions In Crystallography, the triclinic Crystal system is one of the 7 lattice Point groups A crystal system is described by three basis vectors Cleavage, in Mineralogy, is the tendency of crystalline materials to split along definite planes creating smooth surfaces of which there are several named types In the field of Mineralogy, fracture is a term used to describe the shape and texture of the surface formed when a Mineral is broken The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium 61-1. 65
Birefringence	+0. Birefringence, or double refraction, is the decomposition of a ray of Light into two rays (the ordinary ray and the extraordinary ray 040
Streak	Bluish white
Specific gravity	2. The streak (also called powder color) of a Mineral is the Color of the powder produced when it is dragged across an unweathered surface Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 6-2. 9
Fusibility	Fusible in heated HCl
Solubility	Soluble in HCl
References	[1][2][3]

Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula CuAl₆(PO₄)₄(OH)₈·4H₂O. Fusibility is the ease with which a material will Melt. Materials such as solder require a low melting point so that when heat is applied to a joint the solder will melt before Hydrochloric acid is the Solution of Hydrogen chloride ( H[[Chlorine Cl]] in water Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Hydrate is a term used in Inorganic chemistry and Organic chemistry to indicate that a substance contains Water. A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 WikipediaNaming A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Copper (ˈkɒpɚ is a Chemical element with the symbol Cu (cuprum and Atomic number 29 WikipediaNaming Phosphorus, (ˈfɒsfərəs is the Chemical element that has the symbol P and Atomic number 15 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Hydrogen (ˈhaɪdrədʒən is the Chemical element with Atomic number 1 Water is a common Chemical substance that is essential for the survival of all known forms of Life. It is rare and valuable in finer grades and has been prized as a gem and ornamental stone for thousands of years owing to its unique hue. A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash An ornamental stone is a stone used as a decoration They differ from Gemstones in that they are not only used for Jewelry. In recent times turquoise, like most other opaque gems, has been devalued by the introduction of treatments, imitations, and synthetics onto the market, some difficult to detect even by experts.

The substance has been known by many names, but the word turquoise was derived around 16th century from the French language either from the word for Turkish (Turquois) or dark-blue stone (pierre turquin). French ( français,) is a Romance language spoken around the world by 118 million people as a native language and by about 180 to 260 million people ^[4] This may have arisen from a misconception: turquoise does not occur in Turkey but was traded at Turkish bazaars to Venetian merchants who brought it to Europe. Turkey (Türkiye known officially as the Republic of Turkey ( is a Eurasian Country that stretches ^[4] The colour, however, has been employed extensively in the decorative tiles adorning Turkish places of worship and homes for hundreds of years, beginning with the Seljuks, and the association quite possibly has caused the name to take root. The Seljuq (also Seljuq Turks, Seldjuks, Seldjuqs, Seljuks; in Turkish Selçuklular; in Ṣaljūqīyān; in

Properties of turquoise

Even the finest of turquoise is fracturable, reaching a maximum hardness of just under 6, or slightly more than window glass. The Mohs scale of mineral hardness characterizes the scratch resistance of various Minerals through the ability of a harder material to scratch a softer material ^[2] Characteristically a cryptocrystalline mineral, turquoise almost never forms single crystals and all of its properties are highly variable. Cryptocrystalline is a rock texture which is so finely crystalline being made up of such minute Crystals that its crystalline nature is only vaguely revealed In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating Its crystal system is proven to be triclinic via X-ray diffraction testing. A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions In Crystallography, the triclinic Crystal system is one of the 7 lattice Point groups A crystal system is described by three basis vectors X-ray scattering techniques are a family of non-destructive analytical techniques which reveal information about the crystallographic structure chemical composition With lower hardness comes lower specific gravity (high 2. Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically 90, low 2. 60) and greater porosity: These properties are dependent on grain size. Porosity is a measure of the void spaces in a material and is measured as a fraction between 0–1 or as a Percentage between 0–100% The lustre of turquoise is typically waxy to subvitreous, and transparency is usually opaque, but may be semitranslucent in thin sections. Lustre (or luster) is a description of the way light interacts with the surface of a Crystal, rock, or Mineral. In Optics, transparency (also called pellucidity) is the Material property of allowing Colour is as variable as the mineral's other properties, ranging from white to a powder blue to a sky blue, and from a blue-green to a yellowish green. The blue is attributed to idiochromatic copper while the green may be the result of either iron impurities (replacing aluminium) or dehydration. Iron (ˈаɪɚn is a Chemical element with the symbol Fe (ferrum and Atomic number 26 Dehydration ( hypohydration) is the removal of Water ( hydro in ancient Greek) from an object

The refractive index (as measured by sodium light, 589. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium Sodium (ˈsoʊdiəm is an element which has the symbol Na( Latin natrium, from Arabic natrun) atomic number 11 atomic mass 22 3 nm) of turquoise is approximately 1. 61 or 1. 62; this is a mean value seen as a single reading on a gemmological refractometer, owing to the almost invariably polycrystalline nature of turquoise. Gemology ( gemmology outside the United States) is the Science, Art and Profession of identifying and evaluating Gemstones A refractometer is an Optical instrument that is used to determine the Refractive index of a substance A reading of 1. 61–1. 65 (birefringence 0. Birefringence, or double refraction, is the decomposition of a ray of Light into two rays (the ordinary ray and the extraordinary ray 040, biaxial positive) has been taken from rare single crystals. An absorption spectrum may also be obtained with a hand-held spectroscope, revealing a line at 432 nanometres and a weak band at 460 nanometres (this is best seen with strong reflected light). A material's absorption spectrum shows the fraction of incident Electromagnetic radiation absorbed by the material over a range of Frequencies. A spectrometer is an Optical instrument used to measure properties of Light over a specific portion of the Electromagnetic spectrum, typically used Under longwave ultraviolet light, turquoise may occasionally fluoresce green, yellow or bright blue; it is inert under shortwave ultraviolet and X-rays. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays Fluorescence is a Luminescence that is mostly found as an X-radiation (composed of X-rays) is a form of Electromagnetic radiation.

Turquoise is insoluble in all but heated hydrochloric acid. Hydrochloric acid is the Solution of Hydrogen chloride ( H[[Chlorine Cl]] in water Its streak is a pale bluish white and its fracture is conchoidal, leaving a waxy lustre. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific A fracture is the (local separation of an object or material into two or more pieces under the action of stress. Conchoidal Fracture describes the way that Brittle materials break when they do not follow any natural planes of separation. Despite its low hardness relative to other gems, turquoise takes a good polish. Turquoise may also be peppered with flecks of pyrite or interspersed with dark, spidery limonite veining. Limonite is an ore consisting in a mixture of hydrated Iron(III oxide-hydroxide of varying composition

Formation

As a secondary mineral, turquoise apparently forms by the action of percolating acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Weathering is the decomposition of earth rocks, Soils and their Minerals through direct contact with the planet's Atmosphere. Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state For example, the copper may come from primary copper sulfides such as chalcopyrite or from the secondary carbonates malachite or azurite; the aluminium may derive from feldspar; and the phosphorus from apatite. Chalcopyrite (ˌkælkoʊˈpaɪraɪt kal-co-pie-right —"kal" as in " cal endar" "co" as in co de is a Copper Malachite is a carbonate mineral normally known as "copper carbonate" with the formula Cu 2 CO3[[hydroxide Azutite may also refer to a blue Green fluorescent protein derivative. Feldspar is the name of a group of rock-forming Minerals which make up as much as 60% of the Earth 's crust. Climate factors appear to play an important role as turquoise is typically found in arid regions, filling or encrusting cavities and fractures in typically highly altered volcanic rocks, often with associated limonite and other iron oxides. In general terms the Climate of a local or region is said to be arid when it is characterized by a severe lack of available Water, to the extent of hindering Plate tectonics and hotspots Divergent plate boundaries At the Limonite is an ore consisting in a mixture of hydrated Iron(III oxide-hydroxide of varying composition In the American southwest turquoise is almost invariably associated with the weathering products of copper sulfide deposits in or around potassium feldspar bearing porphyritic intrusives. In Geology, an intrusion is a body of Igneous rock that has Crystallized from molten Magma below the surface of the Earth. In some occurrences alunite, potassium aluminium sulfate, is a prominent secondary mineral. Alunite, or alumstone is a Mineral that was first observed in the 15th century in Monti della Tolfa, north to Rome, where it was mined Typically turquoise mineralization is restricted to a relatively shallow depth of less than 20 m, although it does occur along deeper fracture zones where secondary solutions have greater penetration or the depth to the water table is greater.

Although the features of turquoise occurrences are consistent with a secondary or supergene origin, some sources refer to a hypogene origin. In Ore deposit Geology, supergene processes or enrichment occur relatively near the surface The hypogene hypothesis, which holds that the aqueous solutions originate at significant depth, from hydrothermal processes. Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat Initially at high temperature, these solutions rise upward to surface layers, interacting with and leaching essential elements from pre-existing minerals in the process. As the solutions cool, turquoise precipitates, lining cavities and fractures within the surrounding rock. This hypogene process is applicable to the original copper sulfide deposition; however, it is difficult to account for the many features of turquoise occurrences by a hypogene process. That said, there are reports of two phase fluid inclusions within turquoise grains that give elevated homogenization temperatures of 90 to 190 ^oC that require explanation. Fluid inclusions are microscopic bubbles of liquid and gas that are trapped within Crystals As Minerals often form from a liquid or aqueous medium tiny Blebs

Turquoise is nearly always cryptocrystalline and massive and assumes no definite external shape. Crystals, even at the microscopic scale, are exceedingly rare. Typically the form is vein or fracture filling, nodular, or botryoidal in habit. In Mineralogy, shape and size give rise to descriptive terms applied to the typical appearance or habit of Crystals The many terms used by mineralogists Stalactite forms have been reported. A stalactite ( Greek stalaktites, (Σταλακτίτης from the word for "drip" and meaning "that which drips" is a type of Speleothem Turquoise may also pseudomorphously replace feldspar, apatite, other minerals, or even fossils. In Geology, a pseudomorph is a Mineral compound resulting from a substitution process in which the appearance and dimensions remain constant but the mineral which FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. Odontolite is fossil bone or ivory that has been traditionally thought to have been altered by turquoise or similar phosphate minerals such as the iron phosphate vivianite. Odontolite, also called bone turquoise or fossil turquoise, is Fossil Bone or Ivory that has been traditionally thought to have Ivory is formed from Dentine and constitutes the bulk of the Teeth and Tusks of animals such as the Elephant, Hippopotamus, Vivianite Fe 3( P[[oxygen O]]42 · 8( H2O) hydrated Iron Phosphate, is a Intergrowth with other secondary copper minerals such as chrysocolla is also common. Chrysocolla (hydrated Copper silicate) is a Mineral, ( Cu, Al)2 H 2 Si 2O5(

Occurrence

Massive turquoise in matrix with quartz from Mineral Park, Arizona. Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in The State of Arizona ( is a state located in the southwestern region of the United States.

Turquoise was among the first gems to be mined, and while many historic sites have been depleted, some are still worked to this day. These are all small-scale, often seasonal operations, owing to the limited scope and remoteness of the deposits. Most are worked by hand with little or no mechanization. However, turquoise is often recovered as a byproduct of large-scale copper mining operations, especially in the United States. The United States of America —commonly referred to as the

Iran

Cutting and grinding turquoise in Meshed, Iran. Mashhad ( literally the place of martyrdom) is the second largest city in Iran and one of the holiest cities in the Shia 1973.

For at least 2,000 years, the region once known as Persia, has remained the most important source of turquoise, for it is here that fine material is most consistently recovered. The Persian Empire was a series of Iranian empires that ruled over the Iranian plateau, the original Persian homeland and beyond in Western Asia This "perfect colour" deposit, which is blue naturally, and turns green when heated due to dehyration, is restricted to a mine-riddled in Neyshabur,^[5][6][7] the 2,012-metre mountain peak of Ali-mersai, which is tens of kilometers from Mashhad, the capital of Khorasan province, Iran. Nishapur, or Neyshābūr ( is a city in the Razavi Khorasan province in northeastern Iran, situated in a fertile plain at the foot Mashhad ( literally the place of martyrdom) is the second largest city in Iran and one of the holiest cities in the Shia For a topic outline on this subject see List of basic Iran topics. A weathered and broken trachyte is host to the turquoise, which is found both in situ between layers of limonite and sandstone, and amongst the scree at the mountain's base. Trachyte is an Igneous, Volcanic rock with an Aphanitic to Porphyritic texture Scree, also called talus and detritic cone, is a term given to broken rock that appears at the bottom of Crags mountain Cliffs or These workings, together with those of the Sinai Peninsula, are the oldest known. The Sinai Peninsula or Sinai ( Coptic: sina; Egyptian Arabic: sina سينا Arabic, sina'a سيناء

Iranian turquoise is often found replacing feldspar. Although it is commonly marred by whitish patches, its colour and hardness are considered superior to the production of other localities. Iranian turquoise has been mined and traded abroad for centuries, and was probably the source of the first material to reach Europe.

Sinai

Since at least the First Dynasty (3000 BCE), and possibly before then, turquoise was used by the Egyptians and was mined by them in the Sinai Peninsula, called "Country of Turquoise" by the native Monitu. The first dynasty of Ancient Egypt is often combined with the second dynasty under the group title Early Dynastic Period of Egypt. This article is about the contemporary North African ethnic group Mining is the extraction of valuable Minerals or other geological materials from the earth usually (but not always from an Ore body The Sinai Peninsula or Sinai ( Coptic: sina; Egyptian Arabic: sina سينا Arabic, sina'a سيناء There are six mines in the region, all on the southwest coast of the peninsula, covering an area of some 650 km². The two most important of these mines, from a historic perspective, are Serabit el-Khadim and Wadi Maghareh, believed to be among the oldest of known mines. Serabit el-Khadim (سرابت الخادم ( Arabic, also transliterated Serabit al-Khadim Serabit el-Khadem is a locality in the south-west Sinai Peninsula where The former mine is situated about 4 kilometres from an ancient temple dedicated to Hathor. In Egyptian mythology, Hathor (Pronounced Hah-Thor ( Egyptian for house of Horus) was originally a personification of the Milky Way

The turquoise is found in sandstone that is, or was originally, overlain by basalt. Basalt (bəˈsɔːlt ˈbeisɔːlt ˈbæsɔːlt is a common Extrusive Volcanic rock. Copper and iron workings are present in the area. Large-scale turquoise mining is not profitable today, but the deposits are sporadically quarried by Bedouin peoples using homemade gunpowder. The Bedouin, (from the Arabic (ar بدوي pl badū) are a desert-dwelling Arab Nomadic pastoralist, or previously Gunpowder is a an explosive mixture of Sulfur, Charcoal and Potassium nitrate (also known as saltpetre/saltpeter that burns rapidly producing volumes In the rainy winter months, miners face a risk from flash flooding; even in the dry season, death from the collapse of the haphazardly exploited sandstone mine walls is not unheard of. A flash flood is a rapid flooding of geomorphic lowlying areas - washes rivers and streams The colour of Sinai material is typically greener than Iranian material, but is thought to be stable and fairly durable. Often referred to as Egyptian turquoise, Sinai material is typically the most translucent, and under magnification its surface structure is revealed to be peppered with dark blue discs not seen in material from other localities.

In proximity to nearby Eilat, Israel, an attractive intergrowth of turquoise, malachite, and chrysocolla is found. Eilat (Hebrew אילת should not be confused with the nearby kibbutz of Eilot (Hebrew אילות For a topic outline on this subject see List of basic Israel topics. This rock is called Eilat stone and is often referred to as Israel's national stone: it is worked by local artisans for sale to tourists. In Geology, rock is a naturally occurring aggregate of Minerals and/or Mineraloids The Earth's outer solid layer the ‘ Lithosphere

United States

A selection of Ancestral Puebloan (Anasazi) turquoise and orange argillite inlay pieces from Chaco Canyon (dated ca. "Anasazi" directs here For the X-Files episode see Anasazi (The X-Files. "Argillite" may also refer to Argillite Kentucky. An argillite (ˈɑrdʒɨlaɪt is a fine-grained Sedimentary rock composed Chaco Culture National Historical Park is a United States National Historical Park and it is a portion of a UNESCO World Heritage Site hosting the densest 1020–1140 CE) show the typical colour range and mottling of American turquoise.

Bisbee turquoise commonly has a hard chocolate brown coloured matrix, and is considered some of the finest in the world.

The Southwest United States is a significant source of turquoise; Arizona, California (San Bernardino, Imperial, and Inyo counties), Colorado (Conejos, El Paso, Lake, and Saguache counties), New Mexico (Eddy, Grant, Otero, and Santa Fe counties) and Nevada (Clark, Elko, Esmerelda County, Eureka, Lander, Mineral County and Nye counties) are (or were) especially rich. The Southwestern area of the United States could be defined as the states west of the Mississippi River, with the qualification of a certain northern limit such as the 37 The State of Arizona ( is a state located in the southwestern region of the United States. California ( is a US state on the West Coast of the United States, along the Pacific Ocean. San Bernardino County is a county in the US state of California. Imperial County is a County located in the Imperial Valley, in the far southeast of the U Inyo County is located in east-central California in the southwestern United States, on the east side of the Sierra Nevada Mountains and south of Yosemite The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. Conejos County is one of the 64 counties of the State of Colorado in the United States. El Paso County is the second most populous of the 64 counties of the State of Colorado of the United States behind Denver County. Lake County is one of the 64 counties of the State of Colorado of the United States. Saguache County is the seventh most extensive of the 64 counties of the State of Colorado of the United States. New Mexico ( is a state located in the southwestern region of the United States of America. Eddy County is a County located in the US state of New Mexico. Grant County is a County located in the US state of New Mexico. Otero County is a County located in the US state of New Mexico. Santa Fe County is a County located in the US state of New Mexico. Nevada ( is a state located in the western region of the United States of America. Clark is an Anglo Saxon Surname derived from the Latin clericus meaning "scribe" "secretary" or a scholar within a religious Esmeralda County is a County in the west of US state of Nevada. EUREKA, often abbreviated as "E!" is a pan-European Research and development funding and coordination organisation The deposits of California and New Mexico were mined by pre-Columbian Native Americans using stone tools, some local and some from as far away as central Mexico. The pre-Columbian era incorporates all period subdivisions in the history and prehistory of the Americas before the appearance of significant European influences Native Americans in the United States are the indigenous peoples from the regions of North America now encompassed by the continental United States The United Mexican States ( or commonly Mexico (ˈmɛksɪkoʊ () is a federal constitutional Republic in North America. Cerrillos, New Mexico is thought to be the location of the oldest mines; prior to the 1920s, the state was the country's largest producer; it is more or less exhausted today. Los Cerrillos is a Census-designated place (CDP in Santa Fe County, New Mexico, United States. Only one mine in California, located at Apache Canyon, operates at a commercial capacity today. Canyon Apache is a Lucky Luke comic written by Goscinny and Morris.

The turquoise occurs as vein or seam fillings, and as compact nuggets; these are mostly small in size. While quite fine material—rivalling Iranian material in both colour and durability—is sometimes found, most American turquoise is of a low grade (called "chalk turquoise"); high iron levels mean greens and yellows predominate, and a typically friable consistency precludes use in jewellery in the turquoise's untreated state. Jewellery (also spelled jewelry, see spelling differences) is a personal Ornament, such as a necklace ring or bracelet made from Gemstones Arizona is currently the most important producer of turquoise by value, with the vivid Bisbee Blue being a good example of the state's natural endowment; much of the Arizona material is recovered as a byproduct of copper mining. Bisbee Blue or Bisbee turquoise refers to the Turquoise that comes from Copper mines located in the vicinity of Bisbee Arizona.

Nevada is the country's other major producer, with more than 120 mines which have yielded significant quantities of turquoise. Unlike elsewhere in the US, most Nevada mines have been worked primarily for their gem turquoise and very little has been recovered as a byproduct of other mining operations. Nevada turquoise is found as nuggets, fracture fillings and in breccias as the cement filling interstices between fragments. Because of the geology of the Nevada deposits, a majority of the material produced is hard and dense, being of sufficient quality that no treatment or enhancement is required. While nearly every county in the state has yielded some turquoise, the chief producers are in Lander and Esmerelda Counties. Most of the turquoise deposits in Nevada occur along a wide belt of tectonic activity that coincides with the state's zone of thrust faulting. This article discusses the geologic usage for the philosophical or architectural usage see Architectonics ' Or see Plate tectonics. It strikes about N15E and extends from the northern part of Elko County, southward down to the California border southwest of Tonopah. Nevada has produced a wide diversity of colours and mixes of different matrix patterns, with turquoise from Nevada coming in various shades of blue, blue-green, and green. Nevada produces some unique shades of bright mint to apple to neon yellow green. Some of this unusually coloured turquoise may contain significant zinc and iron, which is the cause of the beautiful bright green to yellow-green shades. Some of the green to green yellow shades may actually be Variscite or Faustite, which are secondary phosphate minerals similar in appearance to turquoise. Variscite ·2 H2O, hydrated Aluminium phosphate or Berlinite, is a relatively rare phosphate mineral A significant portion of the Nevada material is also noted for its often attractive brown or black limonite veining, producing what is called "spiderweb matrix". While a number of the Nevada deposits were first worked by Native Americans, the total Nevada turquoise production since the 1870s has been estimated at more than 600 tons, including nearly 400 tons from the Carico Lake mine. In spite of increased costs, small scale mining operations continue at a number of turquoise properties in Nevada, including the Godber, Orvil Jack and Carico Lake Mines in Lander County, the Pilot Mountain Mine in Mineral County, and several properties in the Royston and Candelaria areas of Esmerelda County. ^[8]

Untreated turquoise, Nevada USA. Rough nuggets from the McGuinness Mine, Austin; Blue and green cabochons showing spiderweb, Bunker Hill Mine, Royston

In 1912, the first deposit of distinct, single-crystal turquoise was discovered in Lynch Station, Campbell County, Virginia. Campbell County is a county located in the US state &mdash officially " Commonwealth " &mdash of Virginia. The Commonwealth of Virginia ( is an American state The crystals, forming a druse over the mother rock, are very small; 1 mm (0. 04 inches) is considered large. Until the 1980s Virginia was widely thought to be the only source of distinct crystals; there are now at least 27 other localities. ^[9] The specimens are highly valued by collectors.

In an attempt to recoup profits and meet demand, some American turquoise is treated or enhanced to a certain degree. These treatments include innocuous waxing and more controversial procedures, such as dyeing and impregnation (see Treatments). There are however, some American mines which produce materials of high enough quality that no treatment or alterations are required. Any such treatments which have been performed should be disclosed to the buyer on sale of the material.

Other sources

China has been a minor source of turquoise for 3,000 years or more. China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National Gem-quality material, in the form of compact nodules, is found in the fractured, silicified limestone of Yunxian and Zhushan, Hubei province. Limestone is a Sedimentary rock composed largely of the Mineral Calcite ( Calcium carbonate: CaCO3 ( Postal map spelling: Hupeh) is a central province of the People's Republic of China. Additionally, Marco Polo reported turquoise found in present-day Sichuan. Marco Polo ( September 15 1254 – January 9 1324 at earliest but no later than June 1325 was a Venetian trader and explorer ( Postal map spelling: Szechwan and Szechuan) is a province in western China with its capital in Chengdu. Most Chinese material is exported, but a few carvings worked in a manner similar to jade exist. Jade is an Ornamental stone. The term jade is applied to two different rocks that are made up of different Silicate minerals. In Tibet, where green turquoise has long been appreciated, gem-quality deposits purportedly exist in the mountains of Derge and Nagari-Khorsum in the east and west of the region respectively. Definitions of Tibet See also Definitions of Tibet Name In English The English word Tibet, like the word for Tibet in most European Dêgê County () is a county in Garzê Tibetan Autonomous Prefecture in China's Sichuan province ^[10]

Other notable localities include: Afghanistan; Australia (Victoria and Queensland); northern Chile (Chuquicamata); Cornwall; Saxony; Silesia; and Turkestan. Afghanistan /æfˈgænɪstæn/ officially the Islamic Republic of Afghanistan ( Pashto: د افغانستان اسلامي جمهوریت, For a topic outline on this subject see List of basic Australia topics. Queensland is a state of Australia, occupying the north-eastern corner of the mainland continent Chile, officially the Republic of Chile ( Spanish:) is a country in South America occupying a long and narrow Coastal strip wedged between the Chuquicamata, or "Chuqui" as it is more familiarly known is a big open pit Copper mine in the north of Chile, 215 km northeast Cornwall ( Kernow ˈkɛɹnɔʊ is the most southwesterly county of England, on the Peninsula that lies to the west of the River Tamar The Free State of Saxony (Freistaat Sachsen ˈzaksən Swobodny Stat Sakska is the easternmost federal state of Germany. Etymology One theory claims that the name Silesia is derived from the Silingi, who were most likely a Vandalic (East Germanic people Turkestan (literally meaning "Land of the Turks" is a region in Central Asia, which today is largely inhabited by Turkic peoples.

History of its use

Trade in turquoise crafts, such as this freeform pendant dating from 1000–1040 CE, is believed to have brought the Ancestral Puebloans of the Chaco Canyon great wealth.

The pastel shades of turquoise have endeared it to many great cultures of antiquity: it has adorned the rulers of Ancient Egypt, the Aztecs (and possibly other Pre-Columbian Mesoamericans), Persia, Mesopotamia, the Indus Valley, and to some extent in ancient China since at least the Shang Dynasty. Ancient Egypt was an Ancient Civilization in eastern North Africa, concentrated along the lower reaches of the Nile River in what is now Aztec is a term used to refer to certain ethnic groups of central Mexico, particularly those groups who spoke the Nahuatl language and who achieved political Mesoamerica or Meso-America (Mesoamérica is a Region extending approximately from central Mexico to Honduras and Nicaragua, defined The Persian Empire was a series of Iranian empires that ruled over the Iranian plateau, the original Persian homeland and beyond in Western Asia Mesopotamia (from the Greek meaning "land between the rivers" is an area geographically located between the Tigris and Euphrates rivers largely corresponding The Indus Valley Civilization (Mature period 2600&ndash1900 BCE abbreviated IVC, was an ancient Civilization that flourished in the Indus River basin China ( Wade-Giles ( Mandarin) Chung¹kuo² is a cultural region, an ancient Civilization, and depending on perspective a National The Shang Dynasty ( Chinese: 商[[wiktionary 朝|朝]] or Yin Dynasty ( 殷[[wiktionary 代|代]] was according to traditional sources the ^[11] Despite being one of the oldest gems, probably first introduced to Europe (through Turkey) with other Silk Road novelties, turquoise did not become important as an ornamental stone in the West until the 14th century, following a decline in the Roman Catholic Church's influence which allowed the use of turquoise in secular jewellery. Turkey (Türkiye known officially as the Republic of Turkey ( is a Eurasian Country that stretches The Silk Road, or Silk Routes, are an extensive interconnected network of Trade routes across the Asian continent connecting East South and Western Asia with the It was apparently unknown in India until the Mughal period, and unknown in Japan until the 18th century. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country The Mughal Empire ( Persian and self-designation گورکانی; مغلیہ سلطنت) was an Islamic imperial power which ruled most For a topic outline on this subject see List of basic Japan topics. A common belief shared by many of these civilizations held that turquoise possessed certain prophylactic qualities; it was thought to change colour with the wearer's health and protect him or her from untoward forces.

The Aztecs inlaid turquoise, together with gold, quartz, malachite, jet, jade, coral, and shells, into provocative (and presumably ceremonial) mosaic objects such as masks (some with a human skull as their base), knives, and shields. Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in Malachite is a carbonate mineral normally known as "copper carbonate" with the formula Cu 2 CO3[[hydroxide Jet is a geological material and is considered to be a minor gemstone Jade is an Ornamental stone. The term jade is applied to two different rocks that are made up of different Silicate minerals. Precious coral or red coral is the common name given to Corallium rubrum and several related species of marine Coral. Art History Mosaics of the 4th century BC are found in the Macedonian palace-city of Aegae, and they enriched the floors of Hellenistic A mask is an artefact normally worn on the face typically for protection concealment performance or amusement A knife is a handheld sharp-edged instrument consisting of handle attached to a Blade used for cutting A shield is a protective device meant to intercept attacks The term often refers to a device that is held in the hand as opposed to Armour or a Bullet proof vest Natural resins, bitumen and wax were used to bond the turquoise to the objects' base material; this was usually wood, but bone and shell were also used. Resin, not to be confused with Rosin, is a Hydrocarbon Secretion of many Plants particularly coniferous trees. Bitumen is a mixture of organic Liquids that are highly Viscous, black sticky entirely soluble in Carbon disulfide, and composed primarily Wax has traditionally referred to a substance that is secreted by Bees ( Beeswax) and used by them in constructing their Wood is hard fibrous lignified structural tissue produced as secondary Xylem in the stems of Woody plants notably trees but also shrubs Bones are rigid organs that form part of the Endoskeleton of Vertebrates They function to move support and protect the various organs of the body produce Like the Aztecs, the Pueblo, Navajo and Apache tribes cherished turquoise for its amuletic use; the latter tribe believe the stone to afford the archer dead aim. The Pueblo people are a Native American people in the Southwestern United States. The Navajo Nation ( Diné in the Navajo language) is a semi- autonomous Native American homeland covering about 26000 square miles (67339 square Archery is the practice of using a bow or Crossbow to shoot Arrows Archery has historically been used in Hunting and Combat and has Among these peoples turquoise was used in mosaic inlay, in sculptural works, and was fashioned into toroidal beads and freeform pendants. Art History Mosaics of the 4th century BC are found in the Macedonian palace-city of Aegae, and they enriched the floors of Hellenistic The Ancestral Puebloans (Anasazi) of the Chaco Canyon and surrounding region are believed to have prospered greatly from their production and trading of turquoise objects. "Anasazi" directs here For the X-Files episode see Anasazi (The X-Files. Chaco Culture National Historical Park is a United States National Historical Park and it is a portion of a UNESCO World Heritage Site hosting the densest The distinctive silver jewelry produced by the Navajo and other Southwestern Native American tribes today is a rather modern development, thought to date from circa 1880 as a result of European influences. Silver (ˈsɪlvɚ is a Chemical element with the symbol " Ag " (argentum from the Ancient Greek: ἀργήντος - argēntos gen

In Persia, turquoise was the de facto national stone for millennia, extensively used to decorate objects (from turbans to bridles), mosques, and other important buildings both inside and out, such as the Medresseh-I Shah Husein Mosque of Isfahan. The turban (from Persian fa دلبند or دولبند dulband via the Turkish tr tülbent) is a headdress consisting of a long A bridle is a piece of equipment used to control a Horse. The bridle fits over a horse's head and has the purpose of controlling the horse A "mosque" in English refers to all types of buildings dedicated for Islamic worship although there is a distinction in Arabic between the smaller privately owned mosque and the larger Esfahān or Isfahan (historically also rendered as Ispahan or Hispahan, Old Persian: Aspadana, Middle Persian: Spahān The Persian style and use of turquoise was later brought to India following the establishment of the Mughal Empire there, its influence seen in high purity gold jewellery (together with ruby and diamond) and in such buildings as the Taj Mahal. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country Gold (ˈɡoʊld is a Chemical element with the symbol Au (from its Latin name aurum) and Atomic number 79 A Ruby is a pink to blood-red Gemstone, a variety of the Mineral Corundum ( Aluminium oxide) In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in The Taj Mahal (tɑdʒ Persian turquoise was often engraved with devotional words in Arabic script which was then inlaid with gold. Engraving is the practice of incising a design onto a hard usually flat surface by cutting grooves into it Arabic (ar الْعَرَبيّة (informally ar عَرَبيْ) in terms of the number of speakers is the largest living member of the Semitic language

The iconic gold burial mask of Tutankhamun, inlaid with turquoise, lapis lazuli, carnelian and coloured glass. Carnelian, sometimes spelled cornelian, is a red or reddish-brown variant of Chalcedony. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many

Cabochons of imported turquoise, along with coral, was (and still is) used extensively in the silver and gold jewellery of Tibet and Mongolia, where a greener hue is said to be preferred. A cabochon or cabachon is a Gemstone which has been shaped and polished as opposed to Facetted The resulting form is usually a convex top with a Definitions of Tibet See also Definitions of Tibet Name In English The English word Tibet, like the word for Tibet in most European Mongolia (mɒŋˈɡoʊliə, literally Mongol country/nation,) is a Landlocked Country in East Most of the pieces made today, with turquoise usually roughly polished into irregular cabochons set simply in silver, are meant for inexpensive export to Western markets and are probably not accurate representations of the original style.

The Egyptian use of turquoise stretches back as far as the First Dynasty and possibly earlier; however, probably the most well-known pieces incorporating the gem are those recovered from Tutankhamun's tomb, most notably the Pharaoh's iconic burial mask which was liberally inlaid with the stone. The first dynasty of Ancient Egypt is often combined with the second dynasty under the group title Early Dynastic Period of Egypt. Pharaoh is the title given in modern parlance to the ancient Egyptian kings of all periods It also adorned rings and great sweeping necklaces called pectorals. A finger ring is a band worn as a type of ornamental Jewellery around a finger it is the most common current meaning of the word ring. A necklace is an article of Jewellery which is worn around the Neck. Set in gold, the gem was fashioned into beads, used as inlay, and often carved in a scarab motif, accompanied by carnelian, lapis lazuli, and in later pieces, coloured glass. Carnelian, sometimes spelled cornelian, is a red or reddish-brown variant of Chalcedony. Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many Turquoise, associated with the goddess Hathor, was so liked by the Ancient Egyptians that it became (arguably) the first gemstone to be imitated, the fair semblance created by an artificial glazed ceramic product known as faience. In Egyptian mythology, Hathor (Pronounced Hah-Thor ( Egyptian for house of Horus) was originally a personification of the Milky Way The word ceramic is derived from the Greek word κεραμικός ( keramikos) For the architectural material see Glazed architectural terra-cotta. (A similar blue ceramic has been recovered from Bronze Age burial sites in the British Isles. The term Bronze Age refers to a period in human cultural development when the most advanced Metalworking (at least in systematic and widespread use included techniques for The British Isles (Irish variously Na hOileáin Bhriotanacha, Oileáin Iarthair Eorpa, Éire agus an Bhreatain Mhór; Ellanyn Goaldagh Eileanan )

The French conducted archaeological excavations of Egypt from the mid-19th century through the early 20th. This article is about the country For a topic outline on this subject see List of basic France topics. Archaeology, archeology, or archæology (from Greek grc ἀρχαιολογία archaiologia – grc ἀρχαῖος archaīos These excavations, including that of Tutankhamun's tomb, created great public interest in the western world, subsequently influencing jewellery, architecture, and art of the time. The term architecture (from Greek αρχιτεκτονικήarchitektoniki) can be used to mean a process a profession or documentation Art refers to a diverse range of Human activities creations and expressions that are appealing to the Senses or Emotions of a human individual Turquoise, already favoured for its pastel shades since c. 1810, was a staple of Egyptian Revival pieces. Egyptian Revival is an Architectural style that makes use of the motifs and imagery of Ancient Egypt. In contemporary Western use, turquoise is most often encountered cut en cabochon in silver rings, bracelets, often in the Native American style, or as tumbled or roughly hewn beads in chunky necklaces. Lesser material may be carved into fetishes, such as those crafted by the Zuni. This article concerns the concept of fetishism in Anthropology. The Zuni (also spelled Zuñi by the Spanish and in early 20th Century ethnological texts or Ashiwi (as the Zuni refer to themselves in their own While strong sky blues remain superior in value, mottled green and yellowish material is popular with artisans. An artisan, also called a Craftsman, is a skilled manual worker who crafts items that may be functional or strictly decorative including furniture clothing In Western culture, turquoise is also the traditional birthstone for those born in the month of December. Early civilizations such as India and Babylon have attributed gemstones with magical properties

In Judeo-Christian scripture

Turquoise may have significance in Judeo-Christian scripture: In the Book of Exodus, the construction of a "breastplate of judgment" is described as part of the priestly vestments of Aaron (Exodus 28:15–30). Judeo-Christian (or Judaeo-Christian, sometimes written as Judæo-Christian) is a term used to describe the body of concepts and values which are thought to be held Exodus ( Greek: έξοδος eksodos = "departure" is the second book of the Jewish Torah and of the Christian Old Testament. This article is about Aaron the Levite in the Hebrew Bible, the Qu'ran, and other sources Attached to the ephod, the breastplate (Hoshen) was adorned with twelve gemstones set in gold and arranged in four rows, each stone engraved with the name of one of the Twelve Tribes of Israel. An ephod (pronounced either \ē´fod\ or \ef´od\ was a type of object in ancient Israelite culture and was closely connected with oracular practices Hoshen / Choshen is a Hebrew word usually translated as breastplate; in English language contexts it refers to a specific Breastplate A gemstone or gem, also called a precious or semi-precious stone, is a piece of attractive Mineral, which &mdash when cut and polished &mdash See also History of ancient Israel and Judah According to the Bible, the Israelites were the dominant group living in the Land of Israel. Of the four stones in the third row, the first and second have been translated to be turquoise by various scholars and English bible versions (usually not having both as turquoise at the same time); many others disagree, however. ^[12]

In regard to the first of these stones, the translation is based on the Septuagint rendering the identity of the stone as chrysolithos (the masoretic text calls it tarshish, which just refers to Tarshish, a place, and gives no clue to the gem in question); at the time it was written chrysolithos did not mean Chrysolite specifically, but only golden stone (chryso-lithos). The Septuagint (ˈsɛptuədʒɪnt or simply " LXX " is the Koine Greek version of the Hebrew Bible, translated in stages between the The Masoretic Text ( MT) is the Hebrew text of the Jewish Bible ( Tanakh) Tarshish occurs in the Hebrew Bible with these meanings One of the sons of Javan (Genesis 104 The Mineral olivine (when gem-quality also called Peridot) is a Magnesium Iron silicate with the formula ( Mg Chrysolithos is considered by scholars to possibly mean Topaz, Chrysolite, yellow Jasper, yellow Serpentine, or Turquoise - the last of these on the basis that Turquoise contains golden flecks, and that targums identified the stone as being sea coloured. Topaz is a Silicate mineral of Aluminium and Fluorine with the Chemical formula Al 2 Si[[oxygen O]]4( JasPer is a project to create a reference implementation of the codec specified in the JPEG-2000 Part-1 standard (ie The serpentine group describes a group of common rock-forming hydrous Magnesium Iron phyllosilicate (()3 Minerals they A targum ( Hebrew: תרגום plural targumim, lit "translation interpretation" is an Aramaic Translation of the Hebrew Scholars favour stones which are mostly yellow as being the more likely solution, and opaque stones (Jasper or Serpentine) as more likely than translucent ones, on the consideration of nearby stones in the Hoshen.

In regard to the second of these stones, the masoretic text calls it shoham, and the Septuagint calls it Beryllios (Beryl), though elsewhere it translates shoham as onychion (Onyx), or as smaragdos (green stone). The Mineral beryl is a Beryllium Aluminium cyclosilicate with the Chemical formula Be3Al2(SiO36 Onyx is a Cryptocrystalline form of Quartz. The colors of its bands range from white to almost every color (save some shades such as purple or blue Shoham is of uncertain meaning. Following the Septuagint, some people think the stone should be an onyx (and many more traditional English versions of the Bible take this translation), but scholars think that the stone is actually Malachite (because it is green like beryl and smaragdos, cloudy as beryl can be, and in bands like onyx). Malachite is a carbonate mineral normally known as "copper carbonate" with the formula Cu 2 CO3[[hydroxide

Scholars also disagree as to which tribes of the Israelites each stone is meant to represent; traditional sources are in just as much disagreement. See also History of ancient Israel and Judah According to the Bible, the Israelites were the dominant group living in the Land of Israel.

Imitations

The Egyptians were the first to produce an artificial imitation of turquoise, in the glazed earthenware product faience. For the architectural material see Glazed architectural terra-cotta. Later glass and enamel were also used, and in modern times more sophisticated ceramics, porcelain, plastics, and various assembled, pressed, bonded, and sintered products (composed of various copper and aluminium compounds) have been developed: examples of the latter include "Viennese turquoise", made from precipitated aluminium phosphate coloured by copper oleate; and "neolith", a mixture of bayerite and copper phosphate. In a discussion of Material science, enamel (or vitreous enamel or porcelain enamel in U Porcelain is a Ceramic material made by heating raw materials generally including Clay in the form of Kaolin, in a Kiln to temperatures Plastic is the general common term for a wide range of synthetic or semisynthetic organic solid materials suitable for the manufacture of industrial products Sintering is a method for making objects from powder, by heating the material (below its Melting point - solid state sintering until its particles adhere Aluminium phosphate ( Al[[Phosphorus P]] O4) is a Chemical compound. Gibbsite, Al(OH3 is one of the mineral forms of Aluminium hydroxide. Most of these products differ markedly from natural turquoise in both physical and chemical properties, but in 1972 Pierre Gilson introduced one fairly close to a true synthetic (it does differ in chemical composition owing to a binder used, meaning it is best described as a simulant rather than a synthetic). Gilson turquoise is made in both a uniform colour and with black "spiderweb matrix" veining not unlike the natural Nevada material.

Some natural blue to blue-green materials, such as this botryoidal chrysocolla with quartz drusy, are occasionally confused with, or used to imitate turquoise. Chrysocolla (hydrated Copper silicate) is a Mineral, ( Cu, Al)2 H 2 Si 2O5(

The most common imitation of turquoise encountered today is dyed howlite and magnesite, both white in their natural states, and the former also having natural (and convincing) black veining similar to that of turquoise. Howlite, a calcium borosilicate hydroxide ( Ca 2 B 5 Si[[oxygen O]]9(O H)5 is a Silicate Magnesite is not to be confused with Magnetite or Magnemite. Magnesite is Magnesium carbonate, Mg[[carbon Dyed chalcedony, jasper, and marble is less common, and much less convincing. Chalcedony is a Cryptocrystalline form of Silica, composed of very fine intergrowths of the minerals Quartz and Moganite. JasPer is a project to create a reference implementation of the codec specified in the JPEG-2000 Part-1 standard (ie Marble is a nonfoliated Metamorphic rock resulting from the Metamorphism of Limestone, composed mostly of Calcite (a crystalline form of Other natural materials occasionally confused with or used in lieu of turquoise include: variscite and faustite;^[13] chrysocolla (especially when impregnating quartz); lazulite; smithsonite; hemimorphite; wardite; and a fossil bone or tooth called odontolite or "bone turquoise", coloured blue naturally by the mineral vivianite. Variscite ·2 H2O, hydrated Aluminium phosphate or Berlinite, is a relatively rare phosphate mineral Chrysocolla (hydrated Copper silicate) is a Mineral, ( Cu, Al)2 H 2 Si 2O5( Quartz (from German) is the most abundant Mineral in the Earth 's Continental crust (although Feldspar is more common in Lazulite ((MgFe2+Al2(OHPO42 is a blue phosphate-based mineral containing Magnesium, Iron, and Aluminium Smithsonite, or zinc spar, is Zinc Carbonate Zn[[carbon C]] O 3 a mineral ore of zinc Hemimorphite, is a sorosilicate Mineral which has been mined from days of old from the upper parts of Zinc and Lead Ores chiefly Wardite is a hydrous Sodium Aluminium Phosphate Hydroxide mineral with formula Na[[aluminum Al]]3( P[[oxygen O]]42(O FOSSIL is a standard protocol for allowing serial communication for Telecommunications programs under the DOS Operating system. Odontolite, also called bone turquoise or fossil turquoise, is Fossil Bone or Ivory that has been traditionally thought to have Vivianite Fe 3( P[[oxygen O]]42 · 8( H2O) hydrated Iron Phosphate, is a While rarely encountered today, odontolite was once mined in large quantities—specifically for its use as a substitute for turquoise—in southern France. This article is about the country For a topic outline on this subject see List of basic France topics.

These fakes are detected by gemmologists using a number of tests, relying primarily on non-destructive, close examination of surface structure under magnification; a featureless, pale blue background peppered by flecks or spots of whitish material is the typical surface appearance of natural turquoise, while manufactured imitations will appear radically different in both colour (usually a uniform dark blue) and texture (usually granular or sugary). Gemology ( gemmology outside the United States) is the Science, Art and Profession of identifying and evaluating Gemstones Glass and plastic will have a much greater translucency, with bubbles or flow lines often visible just below the surface. Staining between grain boundaries may be visible in dyed imitations.

Some destructive tests may, however, be necessary; for example, the application of diluted hydrochloric acid will cause the carbonates odontolite and magnesite to effervesce and howlite to turn green, while a heated probe may give rise to the acrid smell so indicative of plastic. In Chemistry, a carbonate is a salt or Ester of Carbonic acid. Differences in specific gravity, refractive index, light absorption (as evident in a material's absorption spectrum), and other physical and optical properties are also considered as means of separation. Specific gravity is defined as the ratio of the Density of a given solid or liquid substance to the density of water at a specific temperature and pressure typically The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium A material's absorption spectrum shows the fraction of incident Electromagnetic radiation absorbed by the material over a range of Frequencies. Imitation turquoise is so prevalent that it likely outnumbers real turquoise by a wide margin. Even material used in authentic Native American and Tibetan jewellery is often fake or, at best, heavily treated.

Treatments

An early turquoise mine in the Madan village of Khorasan.

Turquoise is treated to enhance both its colour and durability (i. e. , increased hardness and decreased porosity). Hardness refers to various properties of Matter in the Solid phase that give it high resistance to various kinds of shape change when Force Porosity is a measure of the void spaces in a material and is measured as a fraction between 0–1 or as a Percentage between 0–100% As is so often the case with any precious stones, full disclosure about treatment is frequently not given. It is therefore left to gemologists to detect these treatments in suspect stones using a variety of testing methods—some of which are necessarily destructive. Gemology ( gemmology outside the United States) is the Science, Art and Profession of identifying and evaluating Gemstones For example, the use of a heated probe applied to an inconspicuous spot will reveal oil, wax, or plastic treatment with certainty.

Waxing and Oiling

Historically, light waxing and oiling were the first treatments used in ancient times, providing a wetting effect, thereby enhancing the colour and lustre. This treatment is more or less acceptable by tradition, especially because treated turquoise is usually of a higher grade to begin with. Oiled and waxed stones are prone to "sweating" under even gentle heat or if exposed to too much sun, and they may develop a white surface film or bloom over time. (With some skill, oil and wax treatments can be restored. )

Stabilization

Material treated with plastic or water glass is termed "bonded" or "stabilized" turquoise. This process consists of pressure impregnation of otherwise unsaleable chalky American material by epoxy and plastics (such as polystyrene) and water glass to produce a wetting effect and improve durability. In Chemistry, epoxy or polyepoxide is a Thermosetting Epoxide Polymer that cures (polymerizes and crosslinks when mixed with a Plastic is the general common term for a wide range of synthetic or semisynthetic organic solid materials suitable for the manufacture of industrial products Polystyrene ˌpɒliˈstaɪriːn ( IUPAC Polyphenylethene is an aromatic Polymer made from the aromatic Monomer Styrene E550 redirects here For the Italian locomotive see FS Class E550 Sodium silicate, also known as water glass or liquid glass, available Plastic and water glass treatments are far more permanent and stable than waxing and oiling, and can be applied to material too chemically or physically unstable for oil or wax to provide sufficient improvement. Conversely, stabilization and bonding are rejected by some as too radical an alteration. ^[14]

The epoxy binding technique was first developed in the 1950s and has been attributed to Colbaugh Processing of Arizona, a company that still operates today. The majority of American material is now treated in this manner although it is a costly process requiring many months to complete. Without such impregnation, most American mining operations would be unprofitable.

Dyeing

The use of Prussian blue and other dyes (often in conjunction with bonding treatments) to "enhance" – that is, make uniform or completely change – colour is regarded as fraudulent by some purists,^[14] especially since some dyes may fade or rub off on the wearer. Prussian blue is a very dark blue colorfast non-toxic Pigment – one of the first synthetic Dyes – which was discovered accidentally in Berlin in 1704 Dyes have also been used to darken the veins of turquoise.

Reconstitution

Perhaps the most radical of treatments is "reconstitution", wherein fragments of fine turquoise material, too small to be used individually, are powdered and then bonded to form a solid mass. Much, if not all, of this "reconstituted" material is likely artificial with no natural components, or may have foreign filler material added to it (see Imitations section).

Zachery Processing

Another treatment—the details of which remain undisclosed—is the so-called Zachery Process,^[15] named after its developer, electrical engineer and turquoise trader James E. Electrical engineering, sometimes referred to as electrical and electronic engineering, is a field of Engineering that deals with the study and application of Zachery. This process claims to use only medium grade material at a minimum, leaving the turquoise harder and with a better colour and lustre.

Backing

Since finer turquoise is often found as thin seams, it may be glued to a base of stronger foreign material as a means of reinforcement. Glue or adhesive is a compound that adheres or bonds two items together These stones are termed "Backed" and it is standard practice that all thinly cut turquoise in the Southwestern United States is backed. The United States of America —commonly referred to as the Native indigenous peoples of this region, because of their considerable use and wearing of turquoise, found that backing increased the durability of thinly cut slabs and cabs of turquoise. Native Americans in the United States are the indigenous peoples from the regions of North America now encompassed by the continental United States They observed that if the stone was not backed it would, for the most part, end up cracking. Early backing materials were the casings of old model T batteries and progressed to old phonograph records and most recently to the use of epoxy steel resins. Backing of turquoise is not known outside of the Native American and Southwestern United States jewelry trade. For indigenous peoples in the United States other than Hawaii and Alaska see also Native Americans in the United States. The value of turquoise of the highest quality is not discounted because it is backed and indeed the process is expected for most thinly cut American commercial gemstones.

Valuation and care

Slab of turquoise in matrix showing a large variety of different colouration

Hardness and richness of colour are two of the major factors in determining the value of turquoise; while colour is a matter of individual taste, generally speaking, the most desirable is a strong sky to "robin's egg" blue (in reference to the eggs of the American Robin). The American Robin, Turdus migratorius, is a migratory Songbird of the thrush family In Tibet, however, a greener blue is said to be preferred. Definitions of Tibet See also Definitions of Tibet Name In English The English word Tibet, like the word for Tibet in most European Whatever the colour, turquoise should not be excessively soft or chalky; even if treated, such lesser material (to which most turquoise belongs) is liable to fade or discolour over time and will not hold up to normal use in jewellery.

The mother rock or matrix in which turquoise is found can often be seen as splotches or a network of brown or black veins running through the stone in a netted pattern; this veining may add value to the stone if the result is complementary, but such a result is uncommon. Such material is sometimes described as "spiderweb matrix"; it is most valued in the Southwest United States and Far East, but is not highly appreciated in the Near East where unblemished and vein-free material is ideal (regardless of how complementary the veining may be). The Southwestern area of the United States could be defined as the states west of the Mississippi River, with the qualification of a certain northern limit such as the 37 The Far East is a term often used by people in the Western world to refer to the countries of East Asia. B Syria - Belka Woman from Damascus Arab from Baghdadjpg|thumb|Inhabitants of the Near East late nineteenth century Uniformity of colour is desired, and in finished pieces the quality of workmanship is also a factor; this includes the quality of the polish and the symmetry of the stone. Calibrated stones—that is, stones adhering to standard jewellery setting measurements—may also be more sought after. Like coral and other opaque gems, turquoise is commonly sold at a price according to its physical size in millimetres rather than weight. Precious coral or red coral is the common name given to Corallium rubrum and several related species of marine Coral.

Turquoise is treated in many different ways, some more permanent and radical than others. Controversy exists as to whether some of these treatments should be acceptable, but one can be more or less forgiven universally: This is the light waxing or oiling applied to most gem turquoise to improve its colour and lustre; if the material is of high quality to begin with, very little of the wax or oil is absorbed and the turquoise therefore does not "rely" on this impermanent treatment for its beauty. Wax has traditionally referred to a substance that is secreted by Bees ( Beeswax) and used by them in constructing their An oil is a substance that is in a viscous Liquid state ( "oily") at ambient temperatures or slightly warmer and is All other factors being equal, untreated turquoise will always command a higher price. Bonded and "reconstituted" material is worth considerably less.

Being a phosphate mineral, turquoise is inherently fragile and sensitive to solvents; perfume and other cosmetics will attack the finish and may alter the colour of turquoise gems, as will skin oils, as will most commercial jewelry cleaning fluids. A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Perfume is a mixture of fragrant Essential oils and Aroma compounds Fixatives and Solvents used to give the human body animals objects and living Prolonged exposure to direct sunlight may also discolour or dehydrate turquoise. Care should therefore be taken when wearing such jewels: cosmetics, including sunscreen and hair spray, should be applied before putting on turquoise jewellery, and they should not be worn to a beach or other sun-bathed environment. Sunscreen (also known as sunblock or suntan lotion) is a Lotion, spray or other Topical product that absorbs or reflects the Sun 's Hair spray (also hair lacquer or spritz) is a common household Aqueous solution that is used to keep Hair stiff or in a certain style After use, turquoise should be gently cleaned with a soft cloth to avoid a build up of residue, and should be stored in its own container to avoid scratching by harder gems. Turquoise can also be adversely affected if stored in an airtight container.

See also

• List of minerals

Notes

References