other names: Magnesium silicate hydrate, steatite, soapstone, talc
mineral class: Silicates and germanates
chemical formula: Mg3Si4O10(OH)2
Chemical elements: Magnesium, silicon, oxygen, hydrogen
Similar minerals: Pyrophyllite
colour: in pure form colorless or white
shine: Mother-of-pearl shine
crystal structure: monoclinic
mass density: approx. 2.6
magnetism: not magnetic
Mohs hardness: 1
stroke color: White
transparency: translucent to opaque
talc describes a mineral that belongs to the group of silicates and is also known under the names soapstone, magnesium silicate hydrate and steatite. Basically, talc is colorless and forms bulky, snow-white aggregates, but may appear by various chemical admixtures also greyish, greenish, light brown, yellowish or even reddish. The crystals are of a thin tabular form, while the aggregates, as compact structures, can be both leafless and kidney-shaped and scaly. With a Mohs hardness of 1, talc is considered to be the softest mineral ever. However, under the influence of high temperatures in the furnace, its resistance increases and the Mohs hardness can then increase up to 6. Talc is unevenly broken, shows perfect cleavage and has a greasy to delicate pearlescent shine. The transparency can be both translucent and transparent. Because of its extremely low hardness, talc can easily be scraped off with fingernails, assuming an almost soapy consistency. At the same time, the mineral is neither soluble in water nor in acids.
Origin, occurrence and localities:
The formation of talc is closely linked to hydrothermal processes, which involve the embossing of predominantly basic types of rock and minerals. Talc is therefore often found as filling material between shale layers and in aisles. It mostly occurs in association with dolomite as rock and mineral as well as with calcite, chlorite, magnetite, quartz or actinolite.
The soft and versatile mineral is widely used around the world. In Europe, important deposits are found mainly in Norway, Germany, Switzerland, Poland, Slovakia and the Czech Republic, Hungary and Italy. Russia also has large deposits in the Urals, Japan, South Africa, the United States and Brazil.
Use of talc:
The most well-known use is in water-repellent body powder talc, which is used to care for the skin and to dry moist areas such as baby's diaper area. The pharmaceutical industry also manufactures talc powder bases as the basis for medical products. Talcum powder is also used by athletes during gymnastics to dry their palms and reduces the friction of squeaky rubber soles. However, the use of talcum powder from a health point of view is not without problems, since the inhalation of the finest powder particles can lead to lung damage. In addition, talc is suspected as a cosmetic product to cause tumors. In addition to its use in cosmetics, talc is also used as a filler and is added to paints and varnishes, plastics, ceramics and paper. Despite warnings from many physicians, talc is approved as a food additive and is cited under the name E 553b as a release agent. The use of large fired talc pieces in sculpture, such as vases and sculptures, has been documented for several centuries.