The lid of a soapstone box. The lid is 4 inches wide (10 cm).

Soapstone (also known as steatite or soaprock) is a metamorphic rock, a talc-schist. Metamorphic rock is the result of the transformation of an existing rock type the protolith, in a process called Metamorphism, which means "change The schists form a group of medium-grade Metamorphic rocks chiefly notable for the preponderance of lamellar Minerals such as Micas chlorite It is largely composed of the mineral talc and is rich in magnesium. Talc (derived from the Persian via Arabic talq) is a Mineral composed of Hydrated Magnesium Silicate with Magnesium (mægˈniːziəm is a Chemical element with the symbol Mg, Atomic number 12 Atomic weight 24 It is produced by dynamothermal metamorphism and metasomatism, which occurs at the areas where tectonic plates are subducted, changing rocks by heat and pressure, with influx of fluids, but without melting. Metamorphism can be defined as the solid state recrystallisation of pre-existing rocks due to changes in heat and/or pressure and/or introduction of fluids i Metasomatism is the chemical alteration of a rock by Hydrothermal and other fluids Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere In Geology, a subduction zone is an area on Earth where two tectonic plates meet and move towards one another with one sliding underneath the other It has been a medium for carving for thousands of years.

Petrology

A block of talc

Petrologically, soapstone is composed dominantly of talc, with varying amounts of chlorite and amphiboles (typically tremolite, anthophyllite, and magnesiocummingtonite), and trace to minor FeCr-oxides. In Geology, petrology (from Greek πέτρα petra, rock and λόγος logos, knowledge is the study of rocks and the conditions on which Talc (derived from the Persian via Arabic talq) is a Mineral composed of Hydrated Magnesium Silicate with The chlorites are a group of phyllosilicate Minerals Chlorites can be described by the following four endmembers based on their chemistry via substitution Amphibole (pronounced amfi-bowl defines an important group of generally dark-colored rock-forming inosilicate Minerals composed of double chain SiO4 Tremolite is a member of the Amphibole group of Silicate minerals with composition Ca 2 Mg 5 Si 8 Anthophyllite is an Amphibole Mineral: (Mg Fe7Si8O22(OH2 Magnesium Iron inosilicate Cummingtonite or magnesium iron silicate hydroxide is a metamorphic Amphibole with the Chemical composition ( Mg, Fe)7 An oxide is a Chemical compound containing at least one Oxygen atom as well as at least one other element It may be schistose or massive. The schists form a group of medium-grade Metamorphic rocks chiefly notable for the preponderance of lamellar Minerals such as Micas chlorite Soapstone is formed by the metamorphism of ultramafic protoliths (e. Ultramafic (also referred to as ultrabasic) rocks are igneous and meta -igneous rocks with very low Silica content (less than 45% generally Protolith refers to the precursor Lithology of a Metamorphic rock g. dunite or serpentinite) and the metasomatism of siliceous dolostones. Dunite (ˈduːnaɪt or /ˈdʌnaɪt/ is an igneous, Plutonic rock, of Ultramafic composition with coarse-grained or Phaneritic Serpentinite is a rock composed of one or more Serpentine Minerals Minerals in this group are formed by serpentinization a hydration and metamorphic Metasomatism is the chemical alteration of a rock by Hydrothermal and other fluids Dolostone is a sedimentary Carbonate rock that contains a high percentage of the Mineral Dolomite.

Pyrophyllite, a mineral very similar to talc is sometimes called soapstone in the generic sense since its physical characteristics and industrial uses are similar, and because it is also commonly used as a carving material. Pyrophyllite is a phyllosilicate Mineral species belonging to the Clay family and composed of Aluminium Silicate Hydroxide However this mineral typically does not have such a soapy feel from which soapstone derives its name.

Physical characteristics and uses

Soapstone sculpture on the Hoysala temple at Belur, India [1]

Steatite is relatively soft (because of the high talc content, talc being one on Mohs hardness scale), and may feel soapy when touched, hence the name. The Hoysala Empire ( Kannada: ಹೊಯ್ಸಳ ಸಾಮ್ರಾಜ್ಯ ( pronunciation: in Kannada was a prominent South Indian Kannadiga WikipediaWikiProject Indian cities for details --> Belur ( Kannada:ಬೇಲೂರು is a Panchayat town in Hassan district in the India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country 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 Soapstone is used for inlaid designs, sculpture, coasters, and kitchen countertops and sinks. A beermat is a coaster used to rest glasses of Beer (or other beverages upon Countertop (also counter top, countertopping, or ( British English) worktop) usually refers to a horizontal worksurface in kitchens other food Traditional Inuit carvings often use soapstone, and some Native American groups made bowls, cooking slabs, and other objects from soapstone, particularly during the Late Archaic archaeological period. Inuit (plural the singular Inuk, means "man" or "person" is a general term for a group of culturally similar Indigenous peoples inhabiting Native Americans in the United States are the indigenous peoples from the regions of North America now encompassed by the continental United States ^[1] Soapstone is sometimes used for fireplace surrounds and woodstoves because it can absorb and evenly distribute heat while being easy to manufacture. This is found in many upscale Alaskan homes. It is also used for griddles and other cookware.

Tepe Yahya, an ancient trading city in southeastern Iran, was a centre for the production and distribution of soapstone in the 5th–3rd millennia BC^[2]

Another instance of use in the ancient world is found in Minoan Crete at the Palace of Knossos, where archaeological recovery has included a magnificent libation table made of steatite. Tepe Yahya is an archaeological site in Kerman, Iran, some 220 km south of Kerman and 90 km south-west of Jiroft. Crete ( Greek: Κρήτη transliteration: Krētē, modern transliteration Kriti) is the largest of the Greek islands and the Knossos (alternative spellings Knossus, Cnossus, Greek Κνωσός kno̞ˈso̞s also known as the Knossos Palace is the largest Archaeology, archeology, or archæology (from Greek grc ἀρχαιολογία archaiologia – grc ἀρχαῖος archaīos A libation (spondee in Greek) is a Ritual pouring of a drink as an offering to a god. ^[3]

Soapstone has been used in India for centuries as a soft medium for carving, but unfortunately the world wide demand for soapstone is threatening the habitat of India's tigers. India, officially the Republic of India (भारत गणराज्य inc-Latn Bhārat Gaṇarājya; see also other Indian languages) is a country ^[4] The Hoysala Empire temples were made from soapstone. The Hoysala Empire ( Kannada: ಹೊಯ್ಸಳ ಸಾಮ್ರಾಜ್ಯ ( pronunciation: in Kannada was a prominent South Indian Kannadiga ^[5]

Soapstone is used by welders and fabricators as a marker because, due to its resistance to heat, it remains visible when heat is applied. Welding is a fabrication process that joins materials usually Metals or Thermoplastics by causing coalescence. Fabrication, when used as an industrial term applies to the building of Machines, Structures or Process equipment for the chemical or fertilizer sector Soapstone is used to create molds for the casting of pewter objects. Casting is a manufacturing process by which a liquid material is (usually poured into a mold which Pewter is a Metal Alloy, traditionally between 85 and 99 percent Tin, with the remainder consisting of Copper and Antimony, acting

Soapstone smoking pipes are found, for example, among Native American Indian artifacts. See also Smoking pipe A pipe for Tobacco smoking typically consists of a small chamber (the bowl for the Combustion of the Tobacco ^[6]

Locally quarried soapstone was used for gravemarkers in 19th century northeast Georgia around Dahlonega and Cleveland, as simple field stone and "slot and tab" tombs.

An Egyptian carved and glazed steatite scarab amulet.

The term steatite is sometimes used for soapstone. It may also denote also a type of ceramic material made from soapstone with minor additives and heated to vitrify (to change or make into glass or a glassy substance, especially through heat fusion). The word ceramic is derived from the Greek word κεραμικός ( keramikos) Vitrification is a process of converting a material into a Glass -like Amorphous solid that is free from any Crystalline structure either by the quick removal Glass in the common sense refers to a Hard, Brittle, transparent Solid, such as that used for Windows many It is often used as an insulator or housing for electrical components, due to its durability and electrical characteristics and because it can be pressed into complex shapes before firing. An insulator, also called a Dielectric, is a material that resists the flow of Electric current. It was used for beads and seals in ancient civilizations. Steatite undergoes transformations when heated to temperatures of 1000-1200 °C into enstatite and cristobalite; in the Mohs scale, this corresponds to an increase in hardness from 1 to 5. Enstatite is the magnesium endmember of the Pyroxene Silicate mineral series enstatite (MgSiO3 - ferrosilite (FeSiO3 The mineral cristobalite is a high-temperature polymorph of Quartz and Tridymite. 5-6. 5. ^[7]

Other names

Kisii stone from Kenya is a type of pyrophyllite used by the Kisii people of the Tabaka Hills in Western Kenya. Kisii (also known as Gusii or Kosova is a community of Bantu speakers who inhabit the Kisii District in Nyanza, western Kenya. They use this material to make pots, used to carry fat for massaging into their skin to guard against the elements.

Combarbalite stone, exclusively mined in Combarbala, Chile, is known for its many colors. While they are not visible during mining, they come out after refining.

Palewa and gorara stones are types of Indian soapstone.

A variety of other regional and marketing names for soapstone are used. ^[8]

See also

Steatite in its raw mineral form

• Ultramafic rock
• Talc carbonate
• Serpentinite
• List of minerals

References

External links

• Soapstone carvings
• Poetry in Stone - the magnificient sculptures of Belur & Halebid
• Ancient soapstone bowl (The Central States Archaeological Journal)
• Soapstone Native American Quarries, Maryland (Geological Society of America)
• Prehistoric soapstone use in northeastern Maryland (Antiquity Journal)
• The Blue Rock Soapstone Quarry, Yancey County, NC (North Carolina Office of State Archaeology)