Pyrophyllite is a

phyllosilicate Silicate minerals are rock-forming minerals made up of silicate groups. They are the largest and most important class of minerals and make up approximately 90 percent of Earth's crust. In mineralogy, silica (silicon dioxide, ) is usually consid ...

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. ( ...

composed of

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...

silicate In chemistry, a silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is al ...

hydroxide Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. I ...

: Al₂Si₄O₁₀(OH)₂. It occurs in two forms (

habit A habit (or wont as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously.

s): crystalline folia and compact masses; distinct

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macros ...

s are not known. The folia have a pronounced pearly luster, owing to the presence of a perfect cleavage parallel to their surfaces: they are flexible but not elastic, and are usually arranged radially in fan-like or spherical groups. This variety, when heated , exfoliates and swells up to many times its original volume, hence the name pyrophyllite, from the Greek ''pyro-'' (πυρο-, the combining form of πῦρ fire) and ''phyllos'' (a leaf), given by

R. Hermann R. or r. may refer to: * ''Reign'', the period of time during which an Emperor, king, queen, etc., is ruler. * '' Rex'', abbreviated as R., the Latin word meaning King * ''Regina'', abbreviated as R., the Latin word meaning Queen * or , abbreviat ...

in 1829. The color of both varieties is white, pale green, greyish or yellowish; they are very soft (

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

of 1.0 to 1.5) and are greasy to the touch. The

specific gravity Relative density, or specific gravity, is the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for liquids is nearly always measured with respect to water (molecule), wa ...

is 2.65 - 2.85. The two varieties are thus very similar to

talc Talc, or talcum, is a Clay minerals, clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thi ...

Occurrence

Pyrophyllite occurs in

phyllite Phyllite ( ) is a type of foliated metamorphic rock created from slate that is further metamorphosed so that very fine grained white mica achieves a preferred orientation.Stephen Marshak ''Essentials of Geology'', 3rd ed. It is primarily compo ...

and

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes o ...

ose rocks, often associated with

kyanite Kyanite is a typically blue aluminosilicate mineral, found in aluminium-rich metamorphic pegmatites and sedimentary rock. It is the high pressure polymorph of andalusite and sillimanite, and the presence of kyanite in metamorphic rocks gener ...

, of which it is an alteration product. It also occurs as

hydrothermal Hydrothermal circulation in its most general sense is the circulation of hot water (Ancient Greek ὕδωρ, ''water'',Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon. revised and augmented throughout by Sir Henry Stuart Jones. with th ...

deposits. Typical associated minerals include: kyanite,

andalusite Andalusite is an aluminium nesosilicate mineral with the chemical formula Al2SiO5. This mineral was called andalousite by Delamétehrie, who thought it came from Andalusia, Spain. It soon became clear that it was a locality error, and that the spe ...

topaz Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al Si O( F, OH). It is used as a gemstone in jewelry and other adornments. Common topaz in its natural state is colorless, though trace element impurities can mak ...

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

and

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

. Deposits containing well-crystallized material are found in: * Manuels,

Newfoundland and Labrador Newfoundland and Labrador (; french: Terre-Neuve-et-Labrador; frequently abbreviated as NL) is the easternmost province of Canada, in the country's Atlantic region. The province comprises the island of Newfoundland and the continental region ...

, Canada, talc-like bright white appearance, high grade, no impurities; 21 million ton deposit. Currently 2 square miles owned and operated b
Trinity Resources Ltd
and the surrounding 20 km2 including the Dog Pond and Trout Pond owned by White Fox Silver Resources Inc. *Russia - pale green foliated masses, very like talc in appearance, are found at Beresovsk near

Yekaterinburg Yekaterinburg ( ; rus, Екатеринбург, p=jɪkətʲɪrʲɪnˈburk), alternatively romanized as Ekaterinburg and formerly known as Sverdlovsk ( rus, Свердло́вск, , svʲɪrˈdlofsk, 1924–1991), is a city and the administra ...

in the

Ural Ural may refer to: *Ural (region), in Russia and Kazakhstan *Ural Mountains, in Russia and Kazakhstan *Ural (river), in Russia and Kazakhstan * Ual (tool), a mortar tool used by the Bodo people of India *Ural Federal District, in Russia *Ural econ ...

s. * St. Niklas,

Zermatt Zermatt () is a municipality in the district of Visp in the German-speaking section of the canton of Valais in Switzerland. It has a year-round population of about 5,800 and is classified as a town by the Swiss Federal Statistical Office (FSO). ...

Valais Valais ( , , ; frp, Valês; german: Wallis ), more formally the Canton of Valais,; german: Kanton Wallis; in other official Swiss languages outside Valais: it, (Canton) Vallese ; rm, (Chantun) Vallais. is one of the cantons of Switzerland, 26 ...

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

* Vaastana,

Kristianstad Kristianstad (, ; older spelling from Danish language, Danish ''Christianstad'') is a Urban areas in Sweden, city and the seat of Kristianstad Municipality, Scania County, Sweden with 40,145 inhabitants in 2016. During the last 15 years, it has ...

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

* Near Ottrje,

Ardennes Mountains The Ardennes (french: Ardenne ; nl, Ardennen ; german: Ardennen; wa, Årdene ; lb, Ardennen ), also known as the Ardennes Forest or Forest of Ardennes, is a region of extensive forests, rough terrain, rolling hills and ridges primarily in Be ...

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

Ibitiara Ibitiara is a municipality in the state of Bahia in the North-East region of Brazil. See also *List of municipalities in Bahia This is a list of the municipalities in the state of Bahia (BA), located in the Northeast Region of Brazil. Bahia i ...

Bahia Bahia ( , , ; meaning "bay") is one of the 26 Federative units of Brazil, states of Brazil, located in the Northeast Region, Brazil, Northeast Region of the country. It is the fourth-largest Brazilian state by population (after São Paulo (sta ...

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

Nagano Prefecture is a landlocked prefecture of Japan located in the Chūbu region of Honshū. Nagano Prefecture has a population of 2,052,493 () and has a geographic area of . Nagano Prefecture borders Niigata Prefecture to the north, Gunma Prefecture to the ...

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

* Near Ogilby,

Imperial County Imperial Count (german: Reichsgraf) was a title in the Holy Roman Empire. In the medieval era, it was used exclusively to designate the holder of an imperial county, that is, a fief held directly ( immediately) from the emperor, rather than from ...

at Tres Cerritos,

Mariposa County Mariposa County () is a county in the U.S. state of California. As of the 2020 U.S. Census, the population was 17,131. The county seat is Mariposa. It is located in the western foothills of the Sierra Nevada mountains, north of Fresno, east of ...

, and the Champion mine, White Mountains,

Mono County, California Mono County ( ) is a county located in the east central portion of the U.S. state of California. As of the 2020 census, the population was 13,195, making it the fourth-least populous county in California. The county seat is Bridgeport. The coun ...

, USA * Near

Quartzsite Quartzsite is a town in La Paz County, Arizona, United States. According to the 2020 census, the population was 2,413. Interstate 10 runs directly through Quartzsite which is at the intersection of U.S. Route 95 and Arizona State Route 95 wi ...

La Paz County, Arizona La Paz County is the 15th county in the U.S. state of Arizona, located in the western part of the state. As of the 2020 census, its population was 16,557, making it the second-least populous county in Arizona. The county seat is Parker. Th ...

, USA * Large deposits at the Deep River region of

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

, USA *Graves Mountain,

Lincoln County, Georgia Lincoln County is a county located in the east central portion of the U.S. state of Georgia. As of the 2020 census, the population was 7,690. The county seat is Lincolnton. The county was created on February 20, 1796. Lincoln County is includ ...

, USA In South Africa, major deposits of pyrophyllite occur within the

Ottosdal Ottosdal is a small town situated at an altitude of 1,479 meters (4,855 feet) on the branch railway line from Makwassie in the central North West Province of South Africa. Ottosdal is a farming community engaged in the growing of grains such as m ...

region, where it is mined for the production of a variety of manufactured goods, and blocks are quarried and marketed as "Wonderstone" for the carving of sculptures.Nel, LT., H. Jacobs, J.T. Allen and G.R. Bozzoli 1937. ''Wonderstone''. Geological Survey of South Africa Bulletin no. 8.

Uses

The compact variety of pyrophyllite is used for slate pencils and tailors' chalk (

French chalk Talc, or talcum, is a clay mineral, composed of hydrated magnesium silicate with the chemical formula Mg3Si4O10(OH)2. Talc in powdered form, often combined with corn starch, is used as baby powder. This mineral is used as a thickening age ...

), and is carved by the Chinese into small images and ornaments of various kinds. Other soft compact minerals (

steatite Soapstone (also known as steatite or soaprock) is a talc-schist, which is a type of metamorphic rock. It is composed largely of the magnesium rich mineral talc. It is produced by dynamothermal metamorphism and metasomatism, which occur in the zo ...

and

pinite {{Short pages monitor