Talc block

Talcum Powder

Talc (derived from the Persian via Arabic talq) is a mineral composed of hydrated magnesium silicate with the chemical formula H₂Mg₃(SiO₃)₄ or Mg₃Si₄O₁₀(OH)₂. It occurs as foliated to fibrous masses, its monoclinic crystals being so rare as to be almost unknown. It has a perfect basal cleavage, and the folia are non-elastic, although slightly flexible. It is sectile and very soft, with a hardness of 1 (Talc is the softest of the Mohs' scale of mineral hardness). It has a specific gravity of 2.5–2.8, a waxlike or pearly luster, and is translucent to opaque. Its colour ranges from white to gray or green and it has a distinctly greasy feel. Its streak is white. Image File history File links Talc_block. ... Image File history File links Talc_block. ... Image File history File linksMetadata Download high resolution version (3072x2304, 2236 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Talc Talk:Talc User:Mattman723/photos Metadata This file contains additional information, probably added from the... Image File history File linksMetadata Download high resolution version (3072x2304, 2236 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Talc Talk:Talc User:Mattman723/photos Metadata This file contains additional information, probably added from the... Persian, (local name: FārsÄ« or PārsÄ«), is an Indo-European language spoken in Iran, Afghanistan, Tajikistan and by minorities in Uzbekistan, Turkmenistan, Azerbaijan, Armenia, Georgia, Southern Russia, neighboring countries, and elsewhere. ... The Arabic language ( ), or simply Arabic ( ), is the largest member of the family of Semitic branch of the Afro-Asiatic language family (classification: South Central Semitic) and is closely related to Hebrew, Amharic, and Aramaic. ... Minerals are natural compounds formed through geological processes. ... Hydrates are compounds formed by the union of water with some other substance, generally forming a neutral body, as certain crystallized salts. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... In chemistry, a silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... In chemistry, a silicate is a compound containing an anion in which one or more central silicon atoms are surrounded by electronegative ligands. ... General Name, Symbol, Number magnesium, Mg, 12 Chemical series alkaline earth metals Group, Period, Block 2, 3, s Appearance silvery white Atomic mass 24. ... General Name, Symbol, Number silicon, Si, 14 Chemical series metalloids Group, Period, Block 14, 3, p Appearance as coarse powder, dark gray with bluish tinge Atomic mass 28. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... Hydroxide is a polyatomic ion consisting of oxygen and hydrogen: OH− It has a charge of −1. ... In crystallography, the monoclinic crystal system is one of the 7 lattice point groups. ... Quartz crystal In chemistry and mineralogy, a crystal is a solid in which the constituent atoms, molecules, or ions are packed in a regularly ordered, repeating pattern extending in all three spatial dimensions. ... Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite planes, creating smooth surfaces, of which there are several named types: Basal cleavage: cleavage parallel to the base of a crystal, or to the plane of the lateral axes. ... Elasticity is a branch of physics which studies the properties of elastic materials. ... Look up Sectility on Wiktionary, the free dictionary Sectility is the ability to be cut into pieces. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. ... Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer. ... Relative density (also known as specific gravity) is a measure of the density of a material. ... For the file system called Lustre, see Lustre (file system) Lustre (American English: luster) is a description of the way light interacts with the surface of a crystal, rock or mineral. ... White is the color of things that reflect light of all parts of the visible spectrum equally and are not dull (see grey). ... Gray or grey is a color seen commonly in nature. ... Green is a color with many different shades, all within a wavelength of roughly 520–570 nm. ...

Formation

Talc is a metamorphic mineral resulting from the metamorphism of magnesian minerals such as pyroxene, amphibole, olivine and other similar minerals in the presence of carbon dioxide and water. This is known as talc carbonation and produces a suite of rocks known as talc carbonates. Quartzite, a form of metamorphic rock, from the Museum of Geology at University of Tartu collection. ... Figure 1:Mantle-peridotite xenolith with green peridot olivine and black pyroxene crystals from San Carlos Indian Reservation, Gila Co. ... For the logical fallacy, see Amphibology. ... Olivine basalt The mineral olivine is a magnesium iron silicate with the formula (Mg,Fe)2SiO4. ... Talc carbonate is a geologic term for a suite of rock and mineral compositions found in metamorphic ultramafic rocks. ...

Talc is primarily formed via carbonation of serpentine, via the following reaction;

Serpentine + Carbon Dioxide → Talc + Magnesite + Water Serpentine Serpentine is a group of common rock-forming hydrous magnesium iron phyllosilicate ((Mg, Fe)3Si2O5(OH)4) minerals; it is also often rich in other metal ores, including chromium, manganese, cobalt and nickel. ... Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms. ... Magnesite is magnesium carbonate, MgCO3. ... Water is an odourless substance that is essential to all known forms of life and is known as the universal solvent. ...

Talc can also be formed via a reaction between dolomite and silica, which is typical of skarnification of dolomites via silica flooding in contact metamorphic aureoles; Skarn is a fine grained metamorphic rock that is usually variably colored green or red, occasionally grey, black, brown or white. ...

Dolomite + Silica + Water → Talc + Calcite + Carbon Dioxide Dolomite crystals from Touissite, Morocco Dolomite is the name of both a carbonate rock and a mineral consisting of calcium magnesium carbonate (formula: CaMg(CO3)2) found in crystals. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ... Doubly refracting Calcite from Iceberg claim, Dixon, New Mexico. ...

Talc can also be formed from magnesian chlorite and quartz in blueschist and eclogite metamorphism via the following reaction: Blueschist is a rock that forms by the metamorphism of sodium-rich basic rocks at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to 400 degrees Celsius (cool by metamorphic standards). ... Eclogite is a coarse-grained, mafic-to-ultramafic grouping of metamorphic rocks of special interest on account of the variety of minerals they contain and their microscopic structures and geological relationships. ...

Chlorite + Quartz → Kyanite + Talc + H₂O This discusses some chlorine compounds. ... Quartz is one of the most common minerals in the Earths continental crust. ... Kyanite, whose name derives from the Greek, kyanos, meaning blue, is a typically blue silicate mineral, commonly found in aluminium-rich metamorphic pegmatites and/or sedimentary rock. ...

In this reaction, the ratio of talc and kyanite is dependant on aluminium content with more aluminous rocks favoring production of kyanite. This is typically associated with high-pressure, low-temperature minerals such as phengite, garnet, glaucophane within the lower blueschist facies. Such rocks are typically white, friable, and fibrous, and are known as whiteschist. General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ... Garnet is a group of minerals that have been used since the Bronze Age as gemstones and abrasives. ... Glaucophane is a mineral belonging to the amphibole group, chemical formula Na2(Mg,Fe)3Al2Si8O22(OH)2. ...

Occurrence

Talc is a very common metamorphic mineral in metamorphic belts which contain ultramafic rocks and within whiteschist and blueschist metamorphic terranes. Prime examples of whiteschists include the Franciscan Metamorphic Belt of the western United States, the western European Alps especially in Italy, certain areas of the Musgrave Block, and some collisional orogens such as the Himalayas. Igneous rock which crystallizes from silicate minerals at the highest temperatures is referred to as ultramafic rock. ... Blueschist is a rock that forms by the metamorphism of sodium-rich basic rocks at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to 400 degrees Celsius (cool by metamorphic standards). ... The Musgrave Block is an east-west trending belt of Proterozoic granulite-gneiss basement rocks approximately 500km long. ... Orogeny is the process of mountain building, and as such is both a tectonic structural event, a geographical event and a chronological event, in that orogenic events happen within a time frame, affect certain regions of rocks and crust, and cause distinctive structural phenomena and related tectonic activity. ... Perspective view of the Himalayas and Mount Everest as seen from space looking south-south-east from over the Tibetan Plateau. ...

Talc carbonated ultramafics are typical of many areas of the Archaean cratons, notably the komatiite belts of the Yilgarn Craton in Western Australia. Talc-carbonate ultramafics are also known from the Lachlan Fold Belt, eastern Australia, from Brazil, the Guyana Shield, and from the ophiolite belts of Turkey, Oman and the Middle East. Talc carbonate is a geologic term for a suite of rock and mineral compositions found in metamorphic ultramafic rocks. ... The Archean is a geologic eon; it is a somewhat antiquated term for the time span between 2500 million years before the present and 3800 million years before the present. ... World geologic provinces. ... Komatiites are ultramafic mantle-derived volcanic rocks. ... // The Yilgarn Craton is a huge craton which constitutes the bulk of the Western Australian land mass. ... Emblems: Floral - Kangaroo Paw (Anigozanthos manglesii); Mammal - Numbat (Myrmecobius fasciatus); Bird - Black Swan (Cygnus atratus) Motto: none Slogan or Nickname: Wildflower State Other Australian states and territories Capital Perth Government Const. ... page in progress // Overview Australia is a continent situated on the Indo-Australian Plate. ... Ophiolites are sections of oceanic lithosphere that have been uplifted or emplaced to be exposed within continental crustal rocks. ... A map showing countries commonly considered to be part of the Middle East The Middle East is a region comprising the lands around the southern and eastern parts of the Mediterranean Sea, a territory that extends from the eastern Mediterranean Sea to the Persian Gulf. ...

Notable economic talc occurrences include the Mount Seabrook talc mine, Western Australia, formed upon a polydeformed, layered ultramafic intrusion.

Uses

A coarse grayish-green talc has been called soapstone or steatite and has been used for stoves, sinks, electrical switchboards, etc. Talc finds use as a cosmetic (talcum powder), as a lubricant, and as a filler in paper manufacture. Talc is used in baby powder, an astringent powder used for preventing rashes on the area covered by a diaper (see diaper rash). Most tailor's chalk is talc, as is the chalk often used for welding or metalworking. The lid of a soapstone box to show the characteristic look of the stone. ... An Egyptian carved and glazed steatite scarab amulet. ... Assorted cosmetics and tools Cosmetics ( ) or make-up are substances used to enhance the beauty of the human body. ... It has been suggested that this article or section be merged into Lubrication. ... Piece of A4 paper Paper is a thin material produced by the amalgamation of plant fibres, which are subsequently held together without extra binder, largely by hydrogen bonds and to a large degree by fiber entanglement. ... An astringent substance is a chemical substance that tends to shrink or constrict body tissues, usually locally after topical medicinal application. ... This article or section does not cite its references or sources. ... Diaper rash (US) or nappy rash (UK), is a generic term applied to rashes seen in the diaper area that may be caused by a variety of skin disorders. ... The Needles, part of the extensive Southern England Chalk Formation. ... Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. ... This article or section is in need of attention from an expert on the subject. ...

Talc is also used as food additive or in pharmaceutical products. In the European Community the additive number is E553b. Food additives are substances added to food to preserve flavour or improve its taste and appearance. ... The European Community (EC), most important of two European Communities, was originally founded on March 25, 1957 by the signing of the Treaty of Rome under the name of European Economic Community. ...

Talcum powder has also become widely used as a stretching substance for marijuana. The harvested buds are mixed with the talcum powder so it sticks to the resin. This is done to increase the weight as well as to make it look more potent. The dried resin itself has a similar crystal-like appearance. Marijuana stretched with talcum poses several health threats, short-term damage (pneumonia), and possibly even long-term damage (lung tissue granuloma) caused by inhaling the talcum vapors^{[citation needed]}. A Cannabis sativa plant The drug cannabis, also called marijuana, is produced from parts of the cannabis plant, primarily the cured flowers and gathered trichomes of the female plant. ...

Safety

Several studies have established preliminary links between talc and pulmonary issues,^[1] lung cancer,^[2][3] skin cancer and ovarian cancer.^[4] This is a major concern considering talc's widespread commercial and household use. However, no conclusive study has yet been made to determine either the toxicity and/or carcinogenic nature of talc and the long history of safe use suggests that these concerns are unfounded. The heart and lungs (from an older edition of Grays Anatomy) The lung is an organ belonging to the respiratory system and interfacing to the circulatory system of air-breathing vertebrates. ... Lung cancer is a cancer of the lungs characterized by the presence of malignant tumours. ... Skin cancer is a malignant growth on the skin, which can have many causes, including repeated severe sunburn or long-term exposure to the sun. ... Ovarian cancer is a malignant ovarian neoplasm (an abnormal growth located on the ovaries). ...

The U.S. Food and Drug Administration (FDA) considers non-asbestiform talc, that is talc which does not contain potentially carcinogenic asbestiform amphibole fibers, to be Generally Recognized As Safe (GRAS) for use in cosmetics. The Food and Drug Administration (FDA) is an agency of the United States Department of Health and Human Services and is responsible for regulating food (humans and animal), dietary supplements, drugs (human and animal), cosmetics, medical devices (human and animal) and radiation emitting devices (including non-medical devices), biologics, and... The term carcinogen refers to any form of substance, radionuclide or radiation which is an agent in the promotion or direct involvement in the facilitation of cancer or genomic instability due to the disruption or damage of cellular metabolic changes. ... Fibrous asbestos on muscovite Asbestos Asbestos Asbestos (a misapplication of Latin: asbestos quicklime from Greek : a, not and sbestos, extinguishable) describes any of a group of minerals that can be fibrous, many of which are metamorphic and are hydrous magnesium silicates. ...

See also

• List of minerals
• Serpentinite
• Talc carbonate
• Magnesite
• Blueschist
• Metamorphic rocks
• Asbestos

Gem animals. ... A sample of serpentinite rock, partially made up of chrysotile ASS LIKE THAT=== Formation === Serpentinization is a geological low-temperature and metamorphic process involving heat and water in which low-silica mafic and ultramafic rocks are oxidized and hydrolyzed with water into serpentinite. ... Talc carbonate is a geologic term for a suite of rock and mineral compositions found in metamorphic ultramafic rocks. ... Magnesite is magnesium carbonate, MgCO3. ... Blueschist is a rock that forms by the metamorphism of sodium-rich basic rocks at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to 400 degrees Celsius (cool by metamorphic standards). ... Metamorphic rock is the result of the transformation of a pre-existing rock type, the protolith, in a process called metamorphism, which means change in form, derived from the Greek words meta, change, and morphe, form. The protolith is subjected to extreme heat (>150 degrees Celsius) and pressure causing profound... Fibrous asbestos on muscovite Asbestos Asbestos Asbestos (a misapplication of Latin: asbestos quicklime from Greek : a, not and sbestos, extinguishable) describes any of a group of minerals that can be fibrous, many of which are metamorphic and are hydrous magnesium silicates. ...

References

• mineral.galleries.com
• webmineral.com
• www.mindat.org

1. ^ Hollinger (1990). "Pulmonary toxicity of inhaled and intravenous talc.".
2. ^ National Toxicology Program (1993). "NTP Toxicology and Carcinogenesis Studies of Talc (Non-Asbestiform) in Rats and Mice (Inhalation Studies).".
3. ^ NIOSH Worker Notification Program. "Health effects of mining and milling talc.".(historical)
4. ^ Harlow, Cramer, Bell, et al. (1992). "Perineal exposure to talc and ovarian cancer risk.".