Talc

Talc is easily distinguishable by its extreme softness, color is white, colorless, pale to dark green, or yellowish to brown. Crystals are rare; it is most commonly found in foliated, fibrous, or massive aggregates. It is often found mixed with other minerals, such as serpentine and calcite. Dense, high-purity talc is called steatite. It is a metamorphic mineral found in veins and magnesium-rich rocks. It is often associated with serpentine, tremolite and forsterite and occurs as an alteration product of silica-poor igneous rocks. Talc is widespread and is found in most areas of the world where low-grade metamorphism occurs. The name soapstone is given to compact masses of talc and other minerals due to their soapy or greasy feel.

Association: Actinolite, tremolite, chlorite, pyroxene, vermiculite, serpentine, anthophyllite, dolomite, calcite.

Chemical Properties

Physical Properties of Talc

Optical Properties of Talc

Occurrence

In talc-rich schists or steatite through hydrothermal alteration of ma¯c rocks (steatitization) subsequent to serpentinization during greenschist facies metamorphism. Also formed by thermal low-temperature metamorphism of siliceous dolostones.

Talc Uses

Talc has many uses.

• In the making of paper, paint, plastic, electrik, food, medicine, cosmetics and ceramics
• Due to its resistance to heat, electricity and acids, it is used on laboratory tabletop surfaces and surfaces of power plants.
• Talc is used as cosmetic (talcum powder), as a lubricant and as a filler in paper production.
• It is used to cover the inner parts of the inner tubes and rubber gloves during production to prevent the surfaces from sticking.
• In medicine, talc is used as a pleurodesis agent to prevent recurrent pleural effusion or pneumothorax. In the European Union, the contribution number is E553b.
• The talc can be used as a polishing agent in the polishing stage in the white rice process.
• It is widely used in the ceramic industry both in the body and in the secrets. Low-fire artwork gives whiteness to its bodies and increases thermal expansion against crushing.

Distribution

Of widespread occurrence. Some localities for good crystals or pure material include:

• on Mt. Greiner, Zillertal, Tirol, Austria.
• At Zermatt, Valais, and St. Gotthard, Ticino, Switzerland.
• From the Ptschtal, Trentino-Alto Adige, Italy.
• At the Trimouns talc deposit, six km northeast of Luzenac, Ariµege, France.
• From Goepfersgruen, Bavaria, Germany.
• At Snarum, Norway.
• In the Onotosk deposit, Irkutsk, Siberia, Russia.
• In the USA, near Fowler, St. Lawrence Co., New York; Delta, York Co., Pennsylvania; Smitheld, Providence Co., Rhode Island; Rochester, Windsor Co., Vermont; Holly Springs, Cherokee Co., Georgia; near San Andreas, Calaveras Co., California.

References

• Bonewitz, R. (2012). Rocks and minerals. 2nd ed. London: DK Publishing.
• Handbookofmineralogy.org. (2019). Handbook of Mineralogy. [online] Available at: http://www.handbookofmineralogy.org [Accessed 4 Mar. 2019].
• Mindat.org. (2019). Talc: Mineral information, data and localities.. [online] Available at: https://www.mindat.org/min-727.html [Accessed 4 Mar. 2019].