other names: Magnesium silicate hydrate, steatite, talc
mineral class: Silicates and germanates
chemical formula: Mg3Si4O10(OH)2
Chemical elements: Magnesium, silicon, oxygen, hydrogen
Similar minerals: Pyrophyllite
colour: colorless, white, purple, pink, green, black, blue
crystal structure: monoclinic
mass density: 2,7
magnetism: pure soapstone is not magnetic
Mohs hardness: 1
stroke color: White
transparency: translucent to opaque
use: Arts and crafts, industrial use
General information about the soapstone:
Under the terms soapstone, Steatite and talcum are summarized different natural stones and minerals, which consist predominantly of magnesium silicate hydrate or talc. If the soapstone is one hundred percent built up from talc, it is assigned to the minerals. If admixtures of other substances are included, it is considered as rock.
Depending on the composition, soapstone can occur in different colors, with white, pale pink, purple and grayish specimens being the most common. Also blue, black and green soapstone are often mined, as there are marbled specimens, which often show several, due to mineral admixtures shades. Such rocks often have a magnetism that can be determined with a compass needle. In its pure form, so as a hundred percent talc existing mineral soapstone has a Mohs hardness of only 1 and is therefore so soft that it can be easily scratched with the fingernail and processed. By admixtures, the structure changes, which is why colorful specimens are often much harder and are only partially suitable as a raw material in industry. Such soapstones are preferred because of their optical characteristics and their good formability by artists, especially in sculpture used. The soapstone owes its name to its greasy, shiny appearance and slippery surface. The common name in Switzerland Lavetzstein goes back to Latin and derives from the word "lavare" for "wash" from. It is believed that the rock was named after it was used in the past to make sinks and various vessels for washing and cooking.
Origin and occurrence:
Soapstone forms hydrothermally when basic and above all magnesium-rich rocks decompose. Deposits are located all over the world and are also widespread in Europe. Among the countries in which it is promoted on a large scale include Austria and Switzerland, Italy, France, Finland, Norway and Ukraine. Economically significant deposits are also located in Egypt, India, South Africa, some South American countries, China and Russia.
Use by humans:
The use of soapstone has a long tradition dating back to antiquity. As a material for the production of different commodities and seals, the rock has played an important role for over three millennia. From Finnish soapstone stone ovens are produced, which have an excellent ability of heat storage. Since soapstone is very soft and easy to polish, it is often used as a material in art and in the art therapy of adults and children. Above all, sculptures, but also bowls, lamps and candlesticks as well as pieces of jewelery are often made of marbled specimens. In the selection should be paid to the origin, since soapstone from certain mining areas may contain traces of harmful asbestos.