Thus, a specimen of what appears to be milky quartz would actually be talc, having a soapy feel and being able to be scratched with a fingernail. Introduction Properties Common rock-forming minerals Economic minerals. Introduction Properties Common rock-forming minerals Economic minerals Talc Talc is the softest mineral, demonstrated by its position at the bottom of Mohs' Scale of Hardness with a relative hardness value of 1.
Smaller amounts of the mineral are used in the ceramics industry because of a change in firing technology. In the paint industry, a shift from oil-based paints to latex paints has decreased the use of talc. In the cosmetics industry, many manufacturers have replaced talc with corn starch powder in many products in response to health concerns and litigation. However, the plastics industry is using more talc, as the mineral becomes a more important ingredient in automotive plastics.
The amount of talc used in rubber production has also increased slightly. Mines in the United States have the ability to produce most grades of talc to make the United States self-sufficient. However, some grades of talc can be imported from other countries at lower costs. This reduces employment and revenue and domestic mining and processing companies.
Numerous other countries are minor producers of talc. Soapstone: A rock known as " soapstone " is a massive variety of talc with varying amounts of other minerals such as micas, chlorite, amphiboles, and pyroxenes. It is a soft rock that is easy to work, and that has caused it to be used in a wide variety of dimension stone and sculpture applications. It is used for counter tops, electrical panels, hearthstones, figurines, statuary, and many other projects.
Talc is a mineral that is most often found in the metamorphic rocks of convergent plate boundaries. It forms from at least two processes.
Most large talc deposits in the United States formed when heated waters carrying dissolved magnesium and silica reacted with dolomitic marbles.
A second process of talc formation occurred when heat and chemically active fluids altered rocks such as dunite and serpentinite into talc. Most of the talc deposits in the United States are in metamorphic rocks on the eastern side of the Appalachian Mountains and in rocks metamorphosed in convergent terranes of Washington, Idaho, Montana, California, Nevada, and New Mexico. Deposits of talc are also found in Texas.
Foliated talc: Talc is a metamorphic mineral that frequently exhibits distinct foliation. Most talc in the United States is produced from an open pit mine where the rock is drilled, blasted, and partially crushed in the mining operation. The highest grade ores are produced by selective mining and sorting operations. Great care is taken during the mining process to avoid contaminating the talc with other rock materials.
These other materials can have an adverse effect on the color of the product. Contamination can introduce hard particles that cause problems in applications where talc is being used because of its softness or lubricating properties.
Partially crushed rock is taken from the mine to a mill, where it is further reduced in particle size. Impurities are sometimes removed by froth flotation or mechanical processing. The mills usually produce crushed or finely ground talc that meets customer requirements for particle size, brightness, composition, and other properties. Uses of Talc: Talc is used as a filler, coating, pigment, dusting agent and extender in plastics, ceramics, paint, paper, cosmetics, roofing, rubber and many other products.
Data from the United States Geological Survey. Talc: Foliated talc that has a black color in massive form but cleaves into thin, flexible, inelastic and colorless sheets. The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties.
Inexpensive mineral collections are available in the Geology. Most people use products made from talc every day; however, they don't realize that talc is in the product or the special role that it plays.
It is mainly used as a filler. The platy shape of talc particles can increase the stiffness of products such as polypropylene, vinyl, polyethylene, nylon, and polyester. It can also increase the heat resistance of these products and reduce shrinkage.
Where the plastic is extruded in the manufacturing process, talc's very low hardness produces less abrasion on equipment than harder mineral fillers. When used as a filler in ceramics, talc can improve the firing characteristics of the greenware and the strength of the finished product. View All Videos View Minerals. The Mineral talc. Talc is known for being the softest mineral on earth. It is number 1 on the Mohs hardness scale , and can be easily scratched by a fingernail.
Talc is not commonly seen in collections, as it is usually uninteresting and fairly common, although a few deeply colored and crystallized examples are known and well sought after. Also very popular are the Talc pseudomorph s. Talc forms some very interesting pseudomorphs after many different minerals, and certain localities are known for the specific minerals replace d by Talc.
Health concerns including a rare respiratory disease are known to be associated with Talc in its powder form. Although solid forms of Talc are assumed to be safe, and most concerns are only after prolonged exposure, it is advisable to wash hands after handling Talc.
The term Soapstone may also be used to describe a massive form of Talc. Soapstone is used in ornamental carvings and tilings. Let us know how we can update this page Click for more details. We strive for accurate content and locality information. If you feel any of the content is incorrect, or if you feel we are missing vital locality information, please fill out the form below so we can update the site.
If you are requesting a locality be added, please only include significant locality occurences for the mineral. About Minerals. Link Directory Donations Mobile Site. Chemical Formula. Basic magnesium silicate. White, beige, gray, yellow, brown, pink, purple, blue, green. Rarely colorless.
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