Ruby
Ruby crystal before faceting, length 0. 8 inches (2 cm)
General
Category	Mineral variety
Chemical formula	aluminium oxide with chromium, Al2O3::Cr
Identification
Color	Red, may be brownish or purplish
Crystal habit	Varies with locality. 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 Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 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 Terminated tabular hexagonal prisms.
Crystal system	Trigonal
Cleavage	No true cleavage
Fracture	Uneven or conchoidal
Mohs Scale hardness	9. A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions 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 0
Luster	Vitreous
Refractive index	~1. 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 762-1. 770
Pleochroism	Orangey red, purplish red
Ultraviolet fluorescence	red under longwave
Streak	white
Specific gravity	4. Pleochroism is an Optical phenomenon in which grains of a rock appear to be different colors when observed at different angles under a Petrographic microscope. Fluorescence is a Luminescence that is mostly found as an 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 0
Melting point	2050°C
Solubility	none
Diaphaneity	transparent

Ruby is a pink to blood red gemstone, a variety of the mineral corundum (aluminium oxide). The melting point of a solid is the temperature range at which it changes state from solid to Liquid. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. 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 A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Corundum (from Tamil kurundam குருந்தம் or kuruvindam குருவிந்தம் is a Crystalline form of The common red color is caused mainly by the element chromium. Chromium (ˈkroʊmiəm is a Chemical element which has the symbol Cr and Atomic number 24 Its name comes from ruber, Latin for red. Latin ( lingua Latīna, laˈtiːna is an Italic language, historically spoken in Latium and Ancient Rome. Other varieties of gem-quality corundum are called sapphires. Sapphire (antique greek hyacinthos refers to gem varieties of the mineral Corundum, an Aluminium oxide (Al2O3 when it is a color other than It is considered one of the four precious stones, together with the sapphire, the emerald and the diamond. 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 Sapphire (antique greek hyacinthos refers to gem varieties of the mineral Corundum, an Aluminium oxide (Al2O3 when it is a color other than Emeralds are a variety of the Mineral Beryl (Be3Al2(SiO36 colored Green by trace amounts In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in

Prices of rubies are primarily determined by color. The brightest and best "red" called pigeon blood red, commands a huge premium over other rubies of similar quality. After color follows clarity: similar to diamonds, a clear stone will command a premium, but a ruby without any needle-like rutile inclusions will indicate the stone has been treated one way or another. Rutile is a Mineral composed primarily of Titanium dioxide, Ti[[oxygen O]]2 Cut and carat (size) also determine the price. The carat is a unit of Mass used for measuring gems and Pearls Currently a carat is defined as exactly 200  mg (0

Contents 1 Physical properties 2 Occurrence 3 Treatments and enhancements 4 Synthetic and imitation rubies 5 Records 6 Historical and cultural references 7 Valley of rubies 8 See also 9 References 10 External links

Physical properties

Rubies have a hardness of 9. Hardness refers to various properties of Matter in the Solid phase that give it high resistance to various kinds of shape change when Force 0 on the Mohs scale of mineral hardness. 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 Among the natural gems only diamond is harder, with a Mohs 10. In Mineralogy, diamond is the allotrope of carbon where the carbon atoms are arranged in 0 by definition.

All natural rubies have imperfections in them, including color impurities and inclusions of rutile needles known as "silk". Rutile is a Mineral composed primarily of Titanium dioxide, Ti[[oxygen O]]2 Gemologists use these needle inclusions found in natural rubies to distinguish them from synthetics, simulants, or substitutes. Usually the rough stone is heated before cutting. Almost all rubies today are treated in some form, with heat treatment being the most common practice. However, rubies that are completely untreated but still of excellent quality command a large premium.

Some rubies show a 3-point or 6-point asterism or star. In Gemmology, an asterism is an Optical phenomenon displayed by some rubies, Sapphires and other gems (i These rubies are cut into cabochons to display the effect properly. 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 Asterisms are best visible with a single-light source, and move across the stone as the light moves or the stone is rotated. Such effects occur when light is reflected off the silk (the structurally oriented rutile needle. Rutile is a Mineral composed primarily of Titanium dioxide, Ti[[oxygen O]]2 inclusions) in a certain way. This is one example where inclusions increase the value of a gemstone. Rubies can furthermore show color changes — though this occurs very rarely — and chatoyancy. In Gemology, chatoyancy (or chatoyance) is an optical reflectance effect seen in certain Gemstones Coined from the French "oeil de chat"

Occurrence

Rubies are mined in Myanmar (Burma), Thailand, Sri Lanka, Tanzania, Kenya, Madagascar, and Cambodia, but they have also been found in the U.S. states of Montana, North Carolina and South Carolina. The United States of America —commonly referred to as the A US state is any one of the fifty subnational entities of the United States of America that share Sovereignty with the federal government Montana ( is a state in the Western United States. One-third of the state in the western part contains numerous mountain ranges (approximately 77 named of the northern North Carolina ( is a state located on the Atlantic Seaboard in the southeastern United States South Carolina ( is a state in the southern region ( Deep South) of the United States of America. The Mogok Valley in Upper Myanmar has produced some of the finest rubies, but in recent years very few good rubies have been found there. Mogok (မိုးကုတ် population 150000 is a city in the Pyin Oo Lwin District of the Mandalay Division of Myanmar, located 200 km north of The unique color in Myanmar (Burmese) rubies is described as "pigeon’s blood". They are known in the trade as “Mogok” rubies. In central Myanmar the area of Mong Hsu also produces rubies. The latest ruby deposit to be found in Myanmar is situated in Nam Ya. In 2002 rubies were found in the Waseges River area of Kenya. The Republic of Kenya is a country in East Africa. It is bordered by Ethiopia to the north Somalia to the northeast Tanzania to the south Sometimes spinels are found along with rubies in the same rocks and are mistaken for rubies. The spinels are any of a class of Minerals of general formulation XY2 O 4 which Crystallize in the cubic (isometric However, fine red spinels may approach the average ruby in value.

Treatments and enhancements

Improving the quality of gemstones by treating them is common practice. Some treatments are used in almost all cases and are therefore considered "acceptable". During the late 1990's, a large supply of low-cost materials caused a sudden surge in supply of heat-treated rubies, leading to a downward pressure on ruby prices.

Improvements used include color alteration, improving transparency by dissolving rutile inclusions, healing of fractures (cracks) or even completely filling them.

The most common treatment is using heat, most if not all rubies at the lower end of the market are heat treated on the rough stones to improve color, remove purple tingle, blue patches and silk. These heat treatments typically occur around temperatures of 1800°C (3300°F). ^[1] Some rubies undergo a process of low tube heat, when the stone is heated over charcoal of a temperature of about 1300°C (2400°F) for 20 to 30 minutes. The silk is only partially broken as the color is improved.

A less acceptable treatment, and one which has gained notoriety in recent years is "Lead Glass Filling" of Rubies. By filling the fractures inside the ruby with lead glass the transparency of the stone is dramatically improved making previously unsuited rubies now fit for applications in jewelry. Glass consists of a network former typically Silica (SiO2 and network modifiers including alkali fluxes such as Potassium oxide or Sodium The process is done in 4 steps:

1. The rough stones are pre-polished to eradicate all surface impurities that may affect the process
2. The rough is cleaned with hydrogen fluoride
3. The first heating process during which no fillers are added. Structure HF forms orthorhombic crystals consisting of zig-zag chains of HF molecules The heating process eradicates impurities inside the fractures. Although this can be done at temperatures up to 1400°C (2500°F) it most likely occurs at a temperature of around 900°C (1600°F) since the rutile silk is still intact
4. The second heating process in an electrical oven with different chemical additives. Different solutions and mixes have shown to be successful, however mostly lead-containing glass-powder is used at present. The ruby is dipped into oils, then covered with powder, embedded on a tile and placed in the oven where it is heated at around 900°C (1600°F) for one hour in an oxidizing atmosphere. The orange colored powder transforms upon heating into a transparent to yellow-colored paste, which fills all fractures. After cooling the color of the paste is fully transparent, that dramatically improves the overall transparency of the ruby.

If a color needs to be added, the glass powder can be "enhanced" with copper or other metal oxides as well as elements such as sodium, calcium, potassium etc.

The second heating process can be repeated three to four times, even applying different mixtures. ^[2] When jewelry containing rubies is heated (for repairs) it should not be coated with boracic acid or any other substance, as this can etch the surface; it does not have to be "protected" like a diamond.

Synthetic and imitation rubies

In 1837 Gaudin made the first synthetic rubies by fusing aluminium at a high temperature with a little chromium as a pigment. In 1847 Edelman made white sapphire by fusing alumina in boric acid. In 1877 Frenic and Freil made crystal corundum from which small stones could be cut. Corundum (from Tamil kurundam குருந்தம் or kuruvindam குருவிந்தம் is a Crystalline form of Frimy and Auguste Verneuil manufactured artificial ruby by fusing BaF₂ and Al₂O₃ with a little Chromium at red heat. Auguste Victor Louis Verneuil ( 1856 - 1913) was a French chemist best known for inventing the first commercially viable process for the manufacture of synthetic In 1903 Verneuil announced he could produce synthetic rubies on a commercial scale using this flame fusion process. The Verneuil process, also called flame fusion, was the first commercially successful method of manufacturing synthetic Gemstones developed in 1902 by the French ^[3]

Other processes in which synthetic rubies can be produced are through the Pulling process, flux process, and the hydrothermal process. The Czochralski process is a method of Crystal growth used to obtain Single crystals of Semiconductors (e Hydrothermal synthesis includes the various techniques of crystallizing substances from high-temperature Aqueous solutions at high Vapor pressures also termed "hydrothermal Most synthetic rubies originate from flame fusion, due to the low costs involved. Synthetic rubies may have no imperfections visible to the naked eye but magnification may reveal curves striae and gas bubbles. " Striae " is also a general term referring to thin narrow grooves or channels or a thin line or band especially if several of them are parallel or close together The fewer the number and the less obvious the imperfections, the more valuable the ruby is; unless there are no imperfections (i. e. , a "perfect" ruby), in which case it will be suspected of being artificial. Dopants are added to some manufactured rubies so they can be identified as synthetic, but most need gemmological testing to determine their origin. A dopant, also called doping agent and dope, is an impurity element added to a crystal or semiconductor lattice in low concentrations in order to alter the optical/electrical Gemology ( gemmology outside the United States) is the Science, Art and Profession of identifying and evaluating Gemstones

Imitation rubies are also marketed. Imitation is an advanced Behavior whereby an individual observes and replicates another's Red spinel, red garnet and glass have been falsely named as rubies. Imitations go back to Roman times and already in the 17th century techniques were developed to color foil red -- by burning scarlet wool in the bottom part of the furnace -- which was then placed under the imitation stone. ^[4] Trade terms such as balas ruby for red spinel and rubellite for red tourmaline can mislead unsuspecting buyers. The spinels are any of a class of Minerals of general formulation XY2 O 4 which Crystallize in the cubic (isometric Tourmaline is a Crystal Silicate mineral compounded with elements such as Aluminium, Iron, Magnesium, Sodium, Lithium Tourmaline is a Crystal Silicate mineral compounded with elements such as Aluminium, Iron, Magnesium, Sodium, Lithium Such terms are therefore discouraged from use by many gemological associations such as the Laboratory Manual Harmonisation Committee (LMHC).

Records

• Although pieces of red corundum can be found weighing many kilograms, they are generally not of sufficient quality to be valuable as gemstones. For this reason, auction prices are the best indicator of a stone's true value, and prices do not necessarily correlate with size. As of 2006, the record price paid at auction for a single stone was $5,860,000 for an unnamed 38. 12 carat cabochon-cut ruby. ^[5]

• The Smithsonian's National Museum of Natural History in Washington DC, has received one of the world's largest and finest ruby gemstones. The National Museum of Natural History is a Natural history Museum administered by the Smithsonian Institution, located on the National The spectacular 23. 1-carat Burmese ruby, set in a platinum ring with diamonds, was donated by businessman and philanthropist Peter Buck in memory of his wife Carmen Lúcia. This extraordinary gemstone displays a richly saturated red color combined with an exceptional transparency. The finely proportioned cut provides vivid red reflections. The stone was mined from the famous Mogok region of Burma, now Myanmar in the 1930s. Mogok (မိုးကုတ် population 150000 is a city in the Pyin Oo Lwin District of the Mandalay Division of Myanmar, located 200 km north of Burma, officially the Union of Myanmar ( pjìdàunzṵ mjàmmà nàinŋàndɔ̀ is the largest country by geographical area in mainland Southeast Asia. Burma, officially the Union of Myanmar ( pjìdàunzṵ mjàmmà nàinŋàndɔ̀ is the largest country by geographical area in mainland Southeast Asia. The 1930s were described as an abrupt shift to more radical and conservative lifestyles as countries were struggling to find a solution to the Great Depression. ^[6]

Historical and cultural references

• According to Rebbenu Bachya, and the New International Version, the word odem means "ruby" in the verse Exodus 28:17 (referring to a stone on the Hoshen), and was the stone representing the tribe of Reuben. Bahye ben Asher ( Hebrew: בחיי בן אשר) or Bahye ben Asher ben Halawa also known as the Rabbeinu Behaye, born about the middle of the The New International Version is an English Translation of the Christian Bible. Exodus ( Greek: έξοδος eksodos = "departure" is the second book of the Jewish Torah and of the Christian Old Testament. Hoshen / Choshen is a Hebrew word usually translated as breastplate; in English language contexts it refers to a specific Breastplate Modern Hebrew has taken this meaning. However, odem actually means earth, and is cognate with Adam; in the Middle East, the earth it refers to is certainly reddish, but the Septuagint translates the term as sard (which also means red), which is also the name of a common, somewhat opaque, gem. Cognates in Linguistics are words that have a common origin They may occur within a language such as shirt and skirt as two English words descended from The personal name Adam derives from the Hebrew noun ha adamah meaning "the ground" or "earth" A literal translation is "man of the The Septuagint (ˈsɛptuədʒɪnt or simply " LXX " is the Koine Greek version of the Hebrew Bible, translated in stages between the is a Japanese tuning company and racing team from Toyota Aichi, mainly competing in the Super GT series and specialising in Toyota tuning parts Scholars think the stone intended is probably a sard, as does the King James Version, scholars think that if not a sard it may possibly be the related gem carnelian; it is thought possible that sard and odem here just mean the colour of the stone, and red jasper would therefore also be a possibility. Carnelian, sometimes spelled cornelian, is a red or reddish-brown variant of Chalcedony. JasPer is a project to create a reference implementation of the codec specified in the JPEG-2000 Part-1 standard (ie
• Ruby is the most commonly named precious stone in English translations of the Bible; an example being Proverbs 31: "A virtuous wife is more precious than rubies. The Book of Proverbs is one of the books of the Ketuvim of the Tanakh, and thus also one of the books of the Old Testament. ". The underlying masoretic text doesn't necessarily refer to rubies, however. The Masoretic Text ( MT) is the Hebrew text of the Jewish Bible ( Tanakh) Not only are there issues such as that mentioned with odem, but in the case of Proverbs 31, the masoretic text merely states jewels, and the Septuagint makes Proverbs 31 refer to precious stones (estin lithon ); some English versions of the bible believe that pearls is a better translation here. The Septuagint (ˈsɛptuədʒɪnt or simply " LXX " is the Koine Greek version of the Hebrew Bible, translated in stages between the
• An early recorded note of the transport and trading of rubies arises in the literature on the North Silk Road of China, where in about 100 BC rubies were carried along this ancient trackway moving westward from China. The Northern Silk Road is a Prehistoric Trackway in northern China originating in the early capital of Xi'an and extending north of the A trackway is an ancient route of travel for people and/or animals ^[7]
• The famous lighted "Red Stars" mounted above Kremlin spires, thought to be giant rubies mined in Siberia, are colored glass. The Kremlin stars (Кремлёвские звёзды are the Pentagonal luminescent Ruby stars installed in the 1930s on five towers of the Moscow Kremlin View01jpg|thumb|right|250px|Remains of the Kolomna Kremlin]] Kremlin (Кремль Kreml) is the Russian word for "fortress" "citadel" or "castle" Siberia (Сиби́рь Sibir) is the name given to the vast region constituting almost all of Northern Asia and for the most part currently serving
• Ruby is the birthstone associated with July and of the zodiac sign Cancer. Birthday is the name given to the date of the anniversary of a person's birth Events in July The traditional period known as "fence month" (the closed season for deer in England ended July 9 (date varied Cancer is the fourth Astrological sign in the Zodiac, originating from the constellation of Cancer.
• Ruby is associated with the sun in Vedic astrology. Jyotiṣa ( Sanskrit jyotiṣa, from jyótis- "light heavenly body" also spelled Jyotish and Jyotisha in English
• Ruby is associated with a 40th wedding anniversary. A wedding anniversary is the Anniversary of the date on which a Wedding took place
• Rubies have always been held in high esteem in Asian countries. They were used to ornament armor, scabbards, and harnesses of noblemen in India and China. Rubies were laid beneath the foundation of buildings to secure good fortune to the structure. ^[8]

Valley of rubies

Of the world's rubies, 90% currently derive from Myanmar (Burma) whose red stones are prized for their purity and hue. Burma, officially the Union of Myanmar ( pjìdàunzṵ mjàmmà nàinŋàndɔ̀ is the largest country by geographical area in mainland Southeast Asia. Hue is one of the main properties of a Color described with names such as " Red " " Yellow " etc Thailand buys the majority of Myanmar's gems. The Kingdom of Thailand (ˈtaɪlænd ราชอาณาจักรไทย, râːtɕʰa-ʔaːnaːtɕɑ̀k-tʰɑj Myanmar's "Valley of Rubies", the mountainous Mogok area, 200 km (125 miles) north of Mandalay, is noted for its rare pigeon's blood rubies and blue sapphires. Mogok (မိုးကုတ် population 150000 is a city in the Pyin Oo Lwin District of the Mandalay Division of Myanmar, located 200 km north of Mandalay is the second largest city and the last royal capital of Burma (Myanmar and is the economic and cultural hub of Upper Burma Sapphire (antique greek hyacinthos refers to gem varieties of the mineral Corundum, an Aluminium oxide (Al2O3 when it is a color other than But working conditions in the mines are horrendous. Debbie Stothard of the Alternative ASEAN Network on Burma stated that mining operators used drugs on employees to improve productivity, with needles shared, raising the risk of HIV infection: "These rubies are red with the blood of young people. The Association of Southeast Asian Nations, commonly referred to as ASEAN, ˈɑːsiːɑːn AH-see-ahn in English (the Official language Burma, officially the Union of Myanmar ( pjìdàunzṵ mjàmmà nàinŋàndɔ̀ is the largest country by geographical area in mainland Southeast Asia. Human immunodeficiency virus ( HIV) is a Lentivirus (a member of the Retrovirus family that can lead to acquired immunodeficiency syndrome " Brian Leber (41-year-old jeweler who founded The Jewellers' Burma Relief Project) stated that: "For the time being, Burmese gems should not be something to be proud of. They should be an object of revulsion. It's the only country where one obtains really top quality rubies, but I stopped dealing in them. I don't want to be part of a nation's misery. If someone asks for a ruby now I show them a nice pink sapphire. "^[9] In 2007, following the crackdown on pro-democracy protests in Myanmar, human rights organizations, gem dealers, and US First Lady Laura Bush called for a boycott of a Myanmar gem auction held twice yearly, arguing that the sale of the stones profits the dictatorial regime in that country. The 2007 Burmese anti-government protests were a series of anti-government protests that started in Burma (also known as Union of Myanmar on August 15, Laura Lane Welch Bush (born November 4 1946 is the wife of the forty-third and current President of the United States, George W ^[10]

See also

• List of minerals

References

External links

• International Colored Stone Association's ruby overview page
• Webmineral crystallographic and mineral info
• Farlang's Historical references on rubies: mining, famous rubies etc.
• Mindat Ruby localities

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