What type of rock is talc

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In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. TALC is a metamorphic and hydrothermal mineral which is found typically in the greenschist facies of metamorphic rocks, and in shear zones where it is an alteration product. Talc has recently been found to be widespread in lime stones of many formations ranging in age from Devonian through Recent.

Where present, it is almost invariably accompanied by chlorite; other clay minerals may or may not be present. The occurrence of talc has also been noted in sandstones and shales, but in these rocks it is extremely uncommon.

Griffin, G. Sedimentary Petrology , 33 , Stewart, F. Yorkshire Geol. Langbein, R. Erde , 21 , CAS Google Scholar. Raymond, L. London , , 39 Article Google Scholar. Naturally, this substance is hydrophobic dislikes water , and tends not to absorb water, therefore giving some of its favourable water-resistant characteristics.

Both of these minerals are nearly identical, each being very soft. Both can be easily crushed and cut, because they are so soft.

Also both have perfect cleavage in one direction, allowing these minerals to break into thin sheets. Each feels greasy to the touch, this is why talc is used for a lubricant, and both are formed in metamorphic environments.

Madoc, Ontario. Some replacements for talc when manufacturing ceramics are clays and pyrophyllite. Kaolin and mica can be substituted instead of talc in rubber paint and plastics production. For paper production, kaolin can be used in place of talc.

There is an abundance of talc with sufficient amounts for many decades to come, but some of these alternatives may be cost-effective depending on the cost of talc. Talc was first discovered on a farm in Madoc in the s.

It was that the Henderson Talc Mine came into production. In the Conley Mine opened in the adjacent property, where there contained a northeast extension of the Henderson ore body. The mines went through various owners until , when the Henderson and Conley mines were merged into one under the name Canadian Talc Limited. More than , tons of high-grade talc has been mined from this deposit to date. Provide Website Feedback.

Department of Earth and Environmental Science. Talc is a hydrothermal mineral formed often at the expense of serpentine which is also an alteration product of olivine and pyroxenes common components of ultramafic rocks. Talc may form as dolomite metamorphoses, but in this case the dolomite needs to be impure. Otherwise, the lack of silica will be limiting the growth of talc. It also seems to be a mineral that easily gets pushed aside by other minerals.

It forms only when the conditions are just right. If we have Al, Ca or K in the precursor rocks, the formation of chlorite, tremolite or phlogopite respectively would be favored. Tremolite is a Ca-bearing amphibole group mineral, phlogopite is a Mg-rich variety of biotite. Talc is usually light green in color. The most common talc-bearing rocks are talc schist and soapstone.

The former is schistose as its name implies and the latter is massive and indeed soapy — its surface is somewhat slippery which is the result of very low hardness. The flakes start slipping in relation to each other if you apply pressure to them with your bare hands, this is what causes the soapy feel. Talc is so soft that you can scratch it with a fingernail and easily cut with a knife.

It is the softest mineral on the Mohs hardness scale with a hardness of 1. However, do not expect that you can easily cut any sample of soapstone also named steatite like a bread because they are composed of intergrown crystals and they often contain other minerals as well.

The softness and waxy feel are useful properties that make the identification of the mineral quite easy. Talc occurs in sand usually as lithic soapstone or schist fragments, but not for very long because it tends to alter to chlorite.