Talc
Image: Didier Descouens (CC BY-SA 4.0)
Mineral NameTalc
Chemical FormulaMg₃Si₄O₁₀(OH)₂
Mohs Hardness1
Crystal Systemmonoclinic
Lusterpearly
Streak Colorwhite
Cleavageperfect basal (one direction)
Fractureuneven
Specific Gravity2.7
Colorswhite, pale green, grey, yellowish, brownish
Transparencytranslucent
Type LocalityWorldwide, including Vermont (USA), Italy, France, India, China
Mineral GroupSilicates
Usestalcum powder, ceramics, paint filler, paper filler, cosmetics, carving stone
Associated Mineralsserpentine, chlorite, dolomite, magnesite, tremolite
Raritycommon
Description
This specimen of talc displays a radiating, foliated habit, with individual crystals appearing as pearly, pale white to yellowish-orange flakes forming a textured surface on a lighter matrix.
Geological Context
Talc is a metamorphic mineral formed from the alteration of magnesium-rich rocks like serpentinites and dolomitic marbles, typically under low-to-medium temperature and pressure conditions. It is commonly found in schistose rocks.
