Gypsum
Desert rose, 10 cm long
General
Category	Mineral
Chemical formula	Calcium Sulfate CaSO4·2H2O
Identification
Color	White to grey, pinkish-red
Crystal habit	Massive, flat. Desert rose is the colloquial name given to rosette formations of the minerals Gypsum and Barite with Poikilotopic sand inclusions The 'petals' 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 Elongated and generally prismatic crystals
Crystal system	Monoclinic 2/m
Twinning	common {110}
Cleavage	good (66° and 114°)
Fracture	Conchoidal, sometimes fibrous
Mohs Scale hardness	1. A crystal system is a category of Space groups which characterize Symmetry of structures in three dimensions with Translational symmetry in three directions Crystal twinning occurs when two separate crystals share some of the same Crystal lattice points in a symmetrical manner 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 5-2
Luster	Vitreous to silky, pearly, or waxy
Refractive index	α=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 520, β=1. 523, γ=1. 530
Optical Properties	2V = 58° +
Pleochroism	None
Streak	White
Specific gravity	2. 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. 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 31 - 2. 33
Fusibility	3
Solubility	hot, dilute HCl
Diaphaneity	transparent to translucent
Major varieties
Satin Spar	Pearly, fibrous masses
Selenite	Transparent and bladed crystals
Alabaster	Fine-grained, slightly colored

Gypsum is a very soft mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO₄·2H₂O. 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 Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. This article is about the Mineral: for other meanings see Selenite (disambiguation. Alabaster is a name applied to varieties of two distinct Minerals Gypsum (a hydrous sulfate of Calcium) and Calcite A mineral is a naturally occurring substance formed through geological processes that has a characteristic chemical composition a highly ordered atomic structure and specific Calcium sulfate is a common laboratory and industrial chemical 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 Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16 Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the Water is a common Chemical substance that is essential for the survival of all known forms of Life. ^[1]

Crystal varieties

Gypsum from New South Wales, Australia

Gypsum occurs in nature as flattened and often twinned crystals and transparent cleavable masses called selenite. For a topic outline on this subject see List of basic Australia topics. Crystal twinning occurs when two separate crystals share some of the same Crystal lattice points in a symmetrical manner In Materials science, a crystal is a Solid in which the constituent Atoms Molecules or Ions are packed in a regularly ordered repeating This article is about the Mineral: for other meanings see Selenite (disambiguation. It may also occur silky and fibrous, in which case it is commonly called satin spar. Finally it may also be granular or quite compact. In hand-sized samples, it can be anywhere from transparent to opaque. A very fine-grained white or lightly-tinted variety of gypsum is called alabaster, which is prized for ornamental work of various sorts. Alabaster is a name applied to varieties of two distinct Minerals Gypsum (a hydrous sulfate of Calcium) and Calcite In arid areas, gypsum can occur in a flower-like form typically opaque with embedded sand grains called desert rose. Desert rose is the colloquial name given to rosette formations of the minerals Gypsum and Barite with Poikilotopic sand inclusions The 'petals' The most visually striking variety, however, is the giant crystals from Naica Mine. The Naica Mine of the Mexican state of Chihuahua is a working mine that is known for its extraordinary Selenite Crystals. Up to the size of 11m long, these megacrystals are among the largest crystals found in nature. A recent publication shows that these crystals are grown under constant temperature such that large crystals can grow slowly but steadily without excessive nucleation. Nucleation is the onset of a Phase transition in a small region ^[2]

Occurrence

Gypsum is a common mineral, with thick and extensive evaporite beds in association with sedimentary rocks. Evaporites (iˈvæpəraɪt are water-soluble Mineral sediments that result from the Evaporation of bodies of surficial Water. Sedimentary rock is one of the three main rock types (the others being igneous and Metamorphic rock) Deposits are known to occur in strata from as early as the Permian age. In Geology and related fields a stratum (plural strata) is a layer of rock or Soil with internally consistent characteristics that distinguishes The Permian is a geologic period and system that extends from 299 ^[3] Gypsum is deposited in lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins. A hot spring is a spring that is produced by the emergence of geothermally heated Groundwater from the earth's crust. Plate tectonics and hotspots Divergent plate boundaries At the In Geology, a vein is a finite volume within a rock, having a distinct shape filled with Crystals of one or more Minerals which were precipitated Hydrothermal anhydrite in veins is commonly hydrated to gypsum by groundwater in near surface exposures. Hydrothermal circulation in its most general sense is the circulation of hot water 'hydros' in the Greek meaning water and 'thermos' meaning heat Anhydrite is a mineral - anhydrous Calcium Sulfate, CaSO4 It is in the Orthorhombic crystal system with three directions of perfect cleavage It is often associated with the minerals halite and sulfur. Halite is the Mineral form of Sodium chloride, Na[[chlorine Cl]] commonly known as rock salt. Sulfur or sulphur (ˈsʌlfɚ see spelling below) is the Chemical element that has the Atomic number 16

Fibrous Gypsum from Brazil

The word gypsum is derived from the aorist form of the Greek verb μαγειρεύω, "to cook", referring to the burnt or calcined mineral. |utc_offset = -2 to -4 |time_zone_DST = BRST |utc_offset_DST = -2 to -5 |cctld Greek (el ελληνική γλώσσα or simply el ελληνικά — "Hellenic" is an Indo-European language, spoken today by 15-22 million people mainly Because the gypsum from the quarries of the Montmartre district of Paris has long furnished burnt gypsum used for various purposes, this material has been called plaster of Paris. A quarry is a type of open-pit mine from which rock or Minerals are extracted Montmartre is a hill (the butte Montmartre) which is 130 metres high giving its name to the surrounding district in the north of Paris in the 18th Paris (ˈpærɨs in English; in French) is the Capital of France and the country's largest city It is also used in foot creams, shampoos and many other hair products. It is water-soluble.

Because gypsum dissolves over time in water, gypsum is rarely found in the form of sand. However, the unique conditions of the White Sands National Monument in the US state of New Mexico have created a 710 km² (275 sq mile) expanse of white gypsum sand, enough to supply the construction industry with drywall for 1,000 years. The White Sands National Monument is a US National Monument located about 25 km (15 New Mexico ( is a state located in the southwestern region of the United States of America. For the musical group "Drywall" see Drywall (musical project Drywall is a common manufactured Building material ^[4] Commercial exploitation of the area, strongly opposed by area residents, was permanently prevented in 1933 when president Herbert Hoover declared the gypsum dunes a protected national monument. Herbert Clark Hoover (August 10 1874 &ndash October 20 1964 was the thirty-first President of the United States (1929–1933

Commercial quantities of gypsum are found in Jamaica, Iran, Thailand, Spain (the main producer in Europe), Germany, Italy, England, Ireland, in British Columbia, Manitoba, Ontario, Nova Scotia and Newfoundland in Canada,^[5] and in New York, Michigan, Indiana^[5],Texas(in the Palo Duro Canyon),Iowa, Kansas, Oklahoma, Arizona, New Mexico, Colorado, Utah and Nevada in the United States. Jamaica (ˈdʒəˈmeɪkə} is an Island nation of the Greater Antilles, in length and as much as in width situated in the Caribbean Sea. For a topic outline on this subject see List of basic Iran topics. The Kingdom of Thailand (ˈtaɪlænd ราชอาณาจักรไทย, râːtɕʰa-ʔaːnaːtɕɑ̀k-tʰɑj Spain () or the Kingdom of Spain (Reino de España is a country located mostly in southwestern Europe on the Iberian Peninsula. Germany, officially the Federal Republic of Germany ( ˈbʊndəsʁepuˌbliːk ˈdɔʏtʃlant is a Country in Central Europe. Italy (Italia officially the Italian Republic, (Repubblica Italiana is located on the Italian Peninsula in Southern Europe, and on the two largest England is a Country which is part of the United Kingdom. Its inhabitants account for more than 83% of the total UK population whilst its mainland Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world British Columbia (ˌbrɪtɨʃ kəˈlʌmbiə ( BC) ( (la Colombie-Britannique C Manitoba (English ˌmænɨˈtoʊbə French /manitoba/ is a province of Canada, spanning 647797 square kilometres (250116  sq mi of North America Ontario (ɒnˈtɛrioʊ is a province located in the central part of Canada, the largest by population and second largest after Quebec Nova Scotia (ˌnəʊvəˈskəʊʃə ( Latin for New Scotland; Alba Nuadh Nouvelle-Écosse is a Canadian province located on Canada 's Newfoundland and Labrador (ˈnuːfɨn(dlənd ən(d ˈlæbrəˌdɔr (Terre-Neuve-et-Labrador is a province of Canada, the tenth and latest to join the Confederation Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page New York ( is a state in the Mid-Atlantic and Northeastern regions of the United States and is the nation's third most populous Michigan ( is a Midwestern state of the United States of America. The State of Indiana ( was the 19th US state admitted into the union Texas ( is a state geographically located in the South Central United States and is also known as the Lone Star State. Palo Duro Canyon is a Canyon system of the Caprock Escarpment in the Panhandle of Texas ( USA) The State of Iowa ( is a state in the Midwestern region of the United States of America. Kansas ( is a Midwestern state in the central region of the United States of America, an area often referred to as the American " Oklahoma ( is a state located in the South Central region of the United States of America. The State of Arizona ( is a state located in the southwestern region of the United States. New Mexico ( is a state located in the southwestern region of the United States of America. The State of Colorado ( or chiefly by nonresidents) is a state located in the Rocky Mountain region of the United States of America. The State of Utah (ˈjuːtɔː or) is a western state of the United States. Nevada ( is a state located in the western region of the United States of America. The United States of America —commonly referred to as the There is also a large mine located at Plaster City, California in Imperial County, and in East Kutai, Kalimantan. Plaster City California, is an unincorporated place in Imperial County in the U In most languages in the world the term Kalimantan refers to the Indonesian portion of the island of Borneo, while for Indonesians the name "Kalimantan"

Vast crystals of gypsum, up to 10 metres in length have been found in the "Cueva de los Crystales" in Naica, Chihuahua, Mexico. The United Mexican States ( or commonly Mexico (ˈmɛksɪkoʊ () is a federal constitutional Republic in North America. ^[6]

Uses of Gypsum

There are a large number of uses for gypsum throughout prehistory and history. Stone Age Paleolithic See also Paleolithic, Recent African Origin, Early Homo sapiens, Early human migrations "Paleolithic" History is the study of the past particularly the written record Those who study history as a Profession are called Historians Etymology Some of these uses are:

Cones of gypsum which formed on the sea floor during the Messinian salinity crisis

• Drywall
• Plaster ingredient. The Messinian Salinity Crisis, also referred to as the Messinian Event, is a period when the Mediterranean Sea evaporated partly or completely dry during the For the musical group "Drywall" see Drywall (musical project Drywall is a common manufactured Building material The term plaster can refer to plaster of Paris Lime plaster, or Cement plaster.
• Fertilizer and soil conditioner. Fertilizers ( also spelt fertiliser are chemical compounds given to Plants to promote growth they are usually applied either through the soil for uptake by plant A soil conditioner, also called a soil amendment, is a material added to Soil to improve plant growth and health In the late eighteenth and early nineteenth century, Nova Scotia gypsum, often referred to as plaister, was a highly sought fertilizer for wheat fields in the United States.
• Plaster of Paris (surgical splints; casting moulds; modeling). The term plaster can refer to plaster of Paris Lime plaster, or Cement plaster.
• A wood substitute in the ancient world; for example, when wood became scarce due to deforestation on Bronze Age Crete, gypsum was employed in building construction at locations where wood was previously used. 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 Crete ( Greek: Κρήτη transliteration: Krētē, modern transliteration Kriti) is the largest of the Greek islands and the ^[7]
• A tofu (soy bean curd) coagulant, making it ultimately a major source of dietary calcium, especially in Asian cultures which traditionally use few dairy products. Tofu, also (the Japanese Romaji spelling doufu (the Chinese Pinyin spelling often used in Chinese recipes or bean curd (the literal Calcium (ˈkælsiəm is the Chemical element with the symbol Ca and Atomic number 20 Dairy products are generally defined as Foodstuffs produced from Milk.
• Adding hardness to water used for homebrewing. Homebrewing typically refers to the Brewing of Beer and similar Alcoholic beverages (and sometimes soft drinks on a very small scale as a Hobby
• Blackboard chalk. Chalk (ʧɔːk is a soft white porous Sedimentary rock, a form of Limestone composed of the Mineral Calcite.
• A component of Portland cement used to prevent flash setting of concrete. Portland cement is the most common type of Cement in general usage in many parts of the world as it is a basic ingredient of Concrete, mortar, Stucco
• Soil/water potential monitoring (soil moisture tension)
• A medicinal agent in traditional Chinese medicine called Shi Gao. Water potential is the Potential energy of Water relative to pure water (e Traditional Chinese medicine (also known as TCM,) includes a range of traditional medical practices originating in China.

References

External links

• WebMineral data
• Mineral Data from Mindat
• Mineral Galleries- Gypsum
• U.S. and National Gypsum Co. mines, Shoals, Martin Co., Indiana, USA