Talc is a
mineralA mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
composed of
hydrateHydrate is a term used in inorganic chemistry and organic chemistry to indicate that a substance contains water. The chemical state of the water varies widely between hydrates, some of which were so labeled before their chemical structure was understood....
d
magnesiumMagnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
silicateA silicate is a compound containing a silicon bearing anion. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O anions. Silicates comprise the majority of the earth's crust, as well as the other...
with the chemical formula H
2Mg
3(SiO
3)
4 or Mg
3Si
4O
10(OH)
2. In loose form, it is the widely-used substance known as talcum powder. It occurs as foliated to fibrous masses, its
crystalA crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...
s 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 the softest known mineral and listed as
1 on the
Mohs hardness scaleThe Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German geologist and mineralogist Friedrich Mohs and is one of several definitions of hardness in...
. It can be easily scratched by a fingernail. It is also sectile (can be cut with a knife). It has a
specific gravitySpecific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
of 2.5–2.8, a clear or dusty
lusterLustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance....
, and is translucent to opaque. Talc is not soluble in water, but it is slightly soluble in dilute
mineral acidA mineral acid is an acid derived from one or more inorganic compounds. A mineral acid is not organic and all mineral acids release hydrogen ions when dissolved in water.-Characteristics:...
s. Its colour ranges from
whiteWhite is a color, the perception of which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in nearly equal amounts and with high brightness compared to the surroundings. A white visual stimulation will be void of hue and grayness.White light can be...
to
greyGrey or gray is an achromatic or neutral color.Complementary colors are defined to mix to grey, either additively or subtractively, and many color models place complements opposite each other in a color wheel. To produce grey in RGB displays, the R, G, and B primary light sources are combined in...
or
greenGreen is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nanometres. In the subtractive color system, it is not a primary color, but is created out of a mixture of yellow and blue, or yellow and cyan; it is considered...
and it has a distinctly greasy feel. Its
streakThe streak of a mineral is the color of the powder produced when it is dragged across an unweathered surface. Unlike the apparent color of a mineral, which for most minerals can vary considerably, the trail of finely ground powder generally has a more consistent characteristic color, and is thus...
is white.
SoapstoneSoapstone is a metamorphic rock, a talc-schist. It is largely composed of the mineral talc and is thus rich in magnesium. It is produced by dynamothermal metamorphism and metasomatism, which occurs in the areas where tectonic plates are subducted, changing rocks by heat and pressure, with influx...
is a
metamorphic rockMetamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
composed predominantly of talc.
Formation
Talc is a
metamorphic mineralMetamorphic rock is the transformation of an existing rock type, the protolith, in a process called metamorphism, which means "change in form". The protolith is subjected to heat and pressure causing profound physical and/or chemical change...
resulting from the metamorphism of magnesian minerals such as serpentine,
pyroxeneThe pyroxenes are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. They share a common structure consisting of single chains of silica tetrahedra and they crystallize in the monoclinic and orthorhombic systems...
,
amphiboleAmphibole is the name of an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures.-Mineralogy:...
,
olivineThe mineral olivine is a magnesium iron silicate with the formula 2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface....
, in the presence of carbon dioxide and water. This is known as
talc carbonation or
steatization and produces a suite of rocks known as
talc carbonateTalc carbonate is a geologic term for a suite of rock and mineral compositions found in metamorphic ultramafic rocks.The term refers to the two most common end-member minerals found within ultramafic rocks which have undergone talc-carbonation or carbonation reactions, talc and the carbonate...
s.
Talc is primarily formed via hydration and carbonation via the following reaction;
- serpentine + carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
→ talc + magnesiteMagnesite is magnesium carbonate, MgCO3. Iron substitutes for magnesium with a complete solution series with siderite, FeCO3. Calcium, manganese, cobalt, and nickel may also occur in small amounts...
+ waterWater is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
- 2 Mg3Si2O5(OH)4 + 3CO2 → Mg3Si4O10(OH)2 + 3 MgCO3 + 3 H2O
Talc can also be formed via a reaction between dolomite and silica, which is typical of
skarnSkarn is an old Swedish mining term originally used to describe a type of silicate gangue, or waste rock, associated with iron-ore bearing sulfide deposits apparently replacing Archean age limestones in Sweden's Persberg mining district. In modern usage the term "skarn" has been expanded to refer...
ification of dolomites via silica-flooding in contact metamorphic aureoles;
- dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
+ silica + water → talc + calciteCalcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
+ carbon dioxide
- 3 CaMg(CO3)2 + 4 SiO2 + H2O → Mg3Si4O10(OH)2 + 3 CaCO3 + 3 CO2
Talc can also be formed from magnesian chlorite and quartz in
blueschistBlueschist is a rock that forms by the metamorphism of basalt and rocks with similar composition at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to ~500 degrees Celsius....
and
eclogiteEclogite is a mafic metamorphic rock. Eclogite is of special interest for at least two reasons. First, it forms at pressures greater than those typical of the crust of the Earth...
metamorphism via the following
metamorphic reactionA metamorphic reaction is a chemical reaction that takes place during the geological process of metamorphism wherein one assemblage of minerals is transformed into a second assemblage which is stable under the new temperature/pressure conditions resulting in the final stable state of the observed...
:
- chlorite
The chlorites are a group of phyllosilicate minerals. Chlorites can be described by the following four endmembers based on their chemistry via substitution of the following four elements in the silicate lattice; Mg, Fe, Ni, and Mn....
+ quartzQuartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
→ kyaniteKyanite, whose name derives from the Greek word kuanos sometimes referred to as "kyanos", meaning deep blue, is a typically blue silicate mineral, commonly found in aluminium-rich metamorphic pegmatites and/or sedimentary rock. Kyanite in metamorphic rocks generally indicates pressures higher than...
+ talc + water
In this reaction, the ratio of talc and kyanite is dependent on
aluminiumAluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
content with more aluminous rocks favoring production of kyanite. This is typically associated with high-pressure, low-temperature minerals such as
phengitePhengite is a series name for dioctahedral micas of composition K224O10, similar to muscovite but with addition of magnesium. It is a non-IMA recognized mineral name representing the series between muscovite and celadonite....
,
garnetThe garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. The name "garnet" may come from either the Middle English word gernet meaning 'dark red', or the Latin granatus , possibly a reference to the Punica granatum , a plant with red seeds...
,
glaucophaneGlaucophane is a mineral belonging to the amphibole group, chemical formula []Na2]Mg3Al2][2|Si8O22].-Name:It is named from its typical blue color . Glaucophane crystallizes in the monoclinic system....
within the lower blueschist facies. Such rocks are typically white, friable, and fibrous, and are known as
whiteschist.
Talc is a tri-octahedral layered mineral; its structure is similar to that of
pyrophyllitePyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al2Si4O102. It occurs in two more or less distinct varieties, namely, as crystalline folia and as compact masses; distinct crystals are not known....
, but with
magnesiumMagnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
in the octahedral sites of the composite layers.
Occurrence
Talc is a common metamorphic mineral in metamorphic belts which contain
ultramafic rocks, such as
soapstoneSoapstone is a metamorphic rock, a talc-schist. It is largely composed of the mineral talc and is thus rich in magnesium. It is produced by dynamothermal metamorphism and metasomatism, which occurs in the areas where tectonic plates are subducted, changing rocks by heat and pressure, with influx...
(a high-talc rock), and within whiteschist and
blueschistBlueschist is a rock that forms by the metamorphism of basalt and rocks with similar composition at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to ~500 degrees Celsius....
metamorphic terranes. Prime examples of whiteschists include the Franciscan Metamorphic Belt of the western
United StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
, the western European
AlpsThe Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
especially in Italy, certain areas of the
Musgrave BlockThe Musgrave Block is an east-west trending belt of Proterozoic granulite-gneiss basement rocks approximately 500km long. The Musgrave Block extends from western South Australia into Western Australia....
, and some collisional
orogensOrogeny refers to forces and events leading to a severe structural deformation of the Earth's crust due to the engagement of tectonic plates. Response to such engagement results in the formation of long tracts of highly deformed rock called orogens or orogenic belts...
such as the
HimalayasThe Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...
which stretches along
PakistanPakistan , officially the Islamic Republic of Pakistan is a sovereign state in South Asia. It has a coastline along the Arabian Sea and the Gulf of Oman in the south and is bordered by Afghanistan and Iran in the west, India in the east and China in the far northeast. In the north, Tajikistan...
,
IndiaIndia , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
,
NepalNepal , officially the Federal Democratic Republic of Nepal, is a landlocked sovereign state located in South Asia. It is located in the Himalayas and bordered to the north by the People's Republic of China, and to the south, east, and west by the Republic of India...
and
BhutanBhutan , officially the Kingdom of Bhutan, is a landlocked state in South Asia, located at the eastern end of the Himalayas and bordered to the south, east and west by the Republic of India and to the north by the People's Republic of China...
.
Talc carbonateTalc carbonate is a geologic term for a suite of rock and mineral compositions found in metamorphic ultramafic rocks.The term refers to the two most common end-member minerals found within ultramafic rocks which have undergone talc-carbonation or carbonation reactions, talc and the carbonate...
ultramafics are typical of many areas of the Archaean
cratonA craton is an old and stable part of the continental lithosphere. Having often survived cycles of merging and rifting of continents, cratons are generally found in the interiors of tectonic plates. They are characteristically composed of ancient crystalline basement rock, which may be covered by...
s, notably the
komatiiteKomatiite is a type of ultramafic mantle-derived volcanic rock. Komatiites have low silicon, potassium and aluminium, and high to extremely high magnesium content...
belts of the
Yilgarn CratonThe Yilgarn Craton is a large craton which constitutes the bulk of the Western Australian land mass. It is bounded by a mixture of sedimentary basins and Proterozoic fold and thrust belts...
in
Western AustraliaWestern Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
. Talc-carbonate ultramafics are also known from the
Lachlan Fold BeltThe Lachlan Fold Belt or Lachlan Orogen is a geological subdivision of the east part of Australia. It is a zone of folded and faulted rocks of similar age. It dominates New South Wales and Victoria, also extending into Tasmania, the Australian Capital Territory and Queensland. It was formed in...
, eastern
AustraliaAustralia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, from
BrazilBrazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, the Guiana Shield, and from the ophiolite belts of
TurkeyTurkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
,
OmanOman , officially called the Sultanate of Oman , is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It is bordered by the United Arab Emirates to the northwest, Saudi Arabia to the west, and Yemen to the southwest. The coast is formed by the Arabian Sea on the...
and the
Middle EastThe Middle East is a region that encompasses Western Asia and Northern Africa. It is often used as a synonym for Near East, in opposition to Far East...
.
Notable economic talc occurrences include the Mount Seabrook talc mine, Western Australia, formed upon a polydeformed, layered ultramafic intrusion. The France-based
Luzenac GroupThe Luzenac Group is a talc mining company headquartered in Toulouse, France. The company is the world's largest producer of talc, with mines and processing plants located in Europe, North America, Australia, and East Asia. The Luzenac Group has been a wholly owned subsidiary of the Rio Tinto...
is the world's largest supplier of mined talc; its largest talc mine at Trimouns near
Luzenac Luzenac is a commune in the Ariège department in southwestern France.-Population:...
in southern France produces 400,000
tonneThe tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s of talc per year, representing 8% of world production.
Uses
Talc is used in many industries such as paper making, plastic, paint and coatings, rubber, food, electric cable, pharmaceuticals, cosmetics, ceramics, etc. A coarse grayish-green high-talc rock is
soapstoneSoapstone is a metamorphic rock, a talc-schist. It is largely composed of the mineral talc and is thus rich in magnesium. It is produced by dynamothermal metamorphism and metasomatism, which occurs in the areas where tectonic plates are subducted, changing rocks by heat and pressure, with influx...
or steatite and has been used for stoves, sinks, electrical switchboards, crayons, soap, etc. It is often used for surfaces of lab counter tops and electrical switchboards because of its resistance to heat, electricity and acids. Talc finds use as a
cosmeticCosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...
(talcum powder), as a
lubricantA lubricant is a substance introduced to reduce friction between moving surfaces. It may also have the function of transporting foreign particles and of distributing heat...
, and as a filler in
paperPaper is a thin material mainly used for writing upon, printing upon, drawing or for packaging. It is produced by pressing together moist fibers, typically cellulose pulp derived from wood, rags or grasses, and drying them into flexible sheets....
manufacture. Talc is used in
baby powderBaby powder is an astringent powder used for preventing diaper rash, as a deodorant, and for other cosmetic uses. It may be composed of talc or corn starch. Talcum powder is harmful if inhaled since it may cause aspiration pneumonia or granuloma. Drugs such as cocaine are sometimes cut with...
, an
astringentAn astringent substance is a chemical compound that tends to shrink or constrict body tissues, usually locally after topical medicinal application. The word "astringent" derives from Latin adstringere, meaning "to bind fast"...
powder used for preventing rashes on the area covered by a
diaperA nappy or a diaper is a kind of pant that allows one to defecate or urinate on oneself discreetly. When diapers become soiled, they require changing; this process is often performed by a second person such as a parent or caregiver...
(see
diaper rashIrritant diaper dermatitis is a generic term applied to skin rashes in the diaper area that are caused by various skin disorders and/or irritants.Generic rash or irritant diaper dermatitis is characterized by joined patches of erythema and...
). It is also often used in
basketballBasketball is a team sport in which two teams of five players try to score points by throwing or "shooting" a ball through the top of a basketball hoop while following a set of rules...
to keep a player's hands dry. Most tailor's
chalkChalk is a soft, white, porous sedimentary rock, a form of limestone composed of the mineral calcite. Calcite is calcium carbonate or CaCO3. It forms under reasonably deep marine conditions from the gradual accumulation of minute calcite plates shed from micro-organisms called coccolithophores....
is talc, as is the chalk often used for
weldingWelding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...
or
metalworkingMetalworking is the process of working with metals to create individual parts, assemblies, or large scale structures. The term covers a wide range of work from large ships and bridges to precise engine parts and delicate jewelry. It therefore includes a correspondingly wide range of skills,...
.
Talc is also used as
food additiveFood additives are substances added to food to preserve flavor or enhance its taste and appearance.Some additives have been used for centuries; for example, preserving food by pickling , salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines...
or in pharmaceutical products as a
glidantA glidant is a substance that is added to a powder to improve its flowability. A glidant will only work at a certain range of concentrations. Above a certain concentration, the glidant will in fact function to inhibit flowability A glidant is a substance that is added to a powder to improve its...
. In medicine talc is used as a
pleurodesisPleurodesis is a medical procedure in which the pleural space is artificially obliterated. It involves the adhesion of the two pleura.- Uses :Pleurodesis is done to prevent recurrence of pneumothorax or recurrent pleural effusion...
agent to prevent recurrent
pleural effusionPleural effusion is excess fluid that accumulates between the two pleural layers, the fluid-filled space that surrounds the lungs. Excessive amounts of such fluid can impair breathing by limiting the expansion of the lungs during ventilation.-Pathophysiology:...
or
pneumothoraxPneumothorax is a collection of air or gas in the pleural cavity of the chest between the lung and the chest wall. It may occur spontaneously in people without chronic lung conditions as well as in those with lung disease , and many pneumothoraces occur after physical trauma to the chest, blast...
. In the
European UnionThe European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
the additive number is E553b.
Talc is widely used in the ceramics industry in both bodies and glazes. In low-fire artware bodies it imparts whiteness and increases thermal expansion to resist
crazingCrazing is a network of fine cracks on the surface of a material, for example in a glaze layer.Crazing is a phenomenon that frequently precedes fracture in some glassy thermoplastic polymers. Crazing occurs in regions of high hydrostatic tension, or in regions of very localized yielding, which...
. In stonewares, small percentages of talc are used to flux the body and therefore improve strength and
vitrificationThe liquid-glass transition is the reversible transition in amorphous materials from a hard and relatively brittle state into a molten or rubber-like state. An amorphous solid that exhibits a glass transition is called a glass...
. It is a source of
MgOMGO may refer to:*Magnesium oxide, the chemical formula MgO*Methylglyoxal, abbreviated MGO*Metal Gear Online, a PlayStation 3 online multiplayer spin-off of the Metal Gear video game series...
flux in high temperature glazes (to control melting temperature). It is also employed as a matting agent in earthenware glazes and can be used to produce magnesia mattes at high temperatures.
ISO standard for quality (ISO 3262)
| Type | Talc content min. wt% | Loss on ignition at 1000 °C, wt % | Solubility in HCl, max. wt % |
| A |
95 |
4 – 6.5 |
5 |
| B |
90 |
4–9 |
10 |
| C |
70 |
4–18 |
30 |
| D |
50 |
4–27 |
30 |
Patents are pending on the use of magnesium silicate as a cement substitute. Its production requirements are less energy-intensive than ordinary
Portland cementPortland cement is the most common type of cement in general use around the world because it is a basic ingredient of concrete, mortar, stucco and most non-specialty grout...
at around 650 °C, while it absorbs far more
carbon dioxideCarbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
as it hardens. This results in a negative
carbon footprintA carbon footprint has historically been defined as "the total set of greenhouse gas emissions caused by an organization, event, product or person.". However, calculating a carbon footprint which conforms to this definition is often impracticable due to the large amount of data required, which is...
overall, as the cement substitute removes 0.6 tonnes of CO
2 per tonne used. This contrasts with a carbon footprint of 0.4 tonne per tonne of conventional cement.
Talc is sometimes used as an adulterant to illegal
heroin, to expand volume and weight and thereby increase its street value. With intravenous use, it may lead to
talcosisPulmonary talcosis, less specifically referred to as talcosis, is a pulmonary disorder caused by talc.It has been related to silicosis resulting from inhalation of talc and silicates. It is also tied to heroin use where talc might be used as an adulterant to increase weight and street value. It is...
, a granulomatous inflammation in the
lungThe lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
s.
Safety
Talc powder is a household item, sold globally for use in personal hygiene and cosmetics and used by many millions every year. Some suspicions have been raised about the possibility its use promotes certain types of diseases, mainly cancers of the ovaries and lungs. This is not widely recognised as an established link.
The studies reference, by subject: pulmonary issues,
lung cancerLung cancer is a disease characterized by uncontrolled cell growth in tissues of the lung. If left untreated, this growth can spread beyond the lung in a process called metastasis into nearby tissue and, eventually, into other parts of the body. Most cancers that start in lung, known as primary...
,
skin cancerSkin neoplasms are skin growths with differing causes and varying degrees of malignancy. The three most common malignant skin cancers are basal cell cancer, squamous cell cancer, and melanoma, each of which is named after the type of skin cell from which it arises...
and
ovarian cancerOvarian cancer is a cancerous growth arising from the ovary. Symptoms are frequently very subtle early on and may include: bloating, pelvic pain, difficulty eating and frequent urination, and are easily confused with other illnesses....
. One of these, published in 1993, was a US National Toxicology Program report, which found that cosmetic grade talc containing no asbestos-like fibres was correlated with tumour formation in
ratsRATS may refer to:* RATS , Regression Analysis of Time Series, a statistical package* Rough Auditing Tool for Security, a computer program...
(
animal testingAnimal testing, also known as animal experimentation, animal research, and in vivo testing, is the use of non-human animals in experiments. Worldwide it is estimated that the number of vertebrate animals—from zebrafish to non-human primates—ranges from the tens of millions to more than 100 million...
) forced to inhale talc for 6 hours a day, five days a week over at least 113 weeks. A 1971 paper found particles of talc embedded in 75% of the ovarian tumors studied.
The US
Food and Drug AdministrationThe Food and Drug Administration is an agency of the United States Department of Health and Human Services, one of the United States federal executive departments...
(FDA) considers talc (magnesium silicate) to be
generally recognized as safeGenerally recognized as safe is an American Food and Drug Administration designation that a chemical or substance added to food is considered safe by experts, and so is exempted from the usual Federal Food, Drug, and Cosmetic Act food additive tolerance requirements.-History:On January 1, 1958,...
(GRAS) for use as an anti-caking agent in table salt in concentrations smaller than 2%.
See also
- Asbestos
Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...
- Blueschist
Blueschist is a rock that forms by the metamorphism of basalt and rocks with similar composition at high pressures and low temperatures, approximately corresponding to a depth of 15 to 30 kilometers and 200 to ~500 degrees Celsius....
- French chalk
French chalk is a form of steatite.As an arist's material the term is used by Max Doerner in his book "The Materials of the Artist" where he describes a calcium carbonate used to make traditional gesso primer, to be painted over...
- List of minerals
- Magnesite
Magnesite is magnesium carbonate, MgCO3. Iron substitutes for magnesium with a complete solution series with siderite, FeCO3. Calcium, manganese, cobalt, and nickel may also occur in small amounts...
- Meerschaum
Meerschaum , also sepiolite, is a soft white mineral sometimes found floating on the Black Sea, and rather suggestive of sea-foam, whence the German origin of the name, as well as the French name for the same substance, écume de mer.-Overview:...
- Metamorphic rocks
- Serpentinite
Serpentinite is a rock composed of one or more serpentine group minerals. Minerals in this group are formed by serpentinization, a hydration and metamorphic transformation of ultramafic rock from the Earth's mantle...
- Talc carbonate
Talc carbonate is a geologic term for a suite of rock and mineral compositions found in metamorphic ultramafic rocks.The term refers to the two most common end-member minerals found within ultramafic rocks which have undergone talc-carbonation or carbonation reactions, talc and the carbonate...
External links