Talc
Mineral Mg3Si4O10(OH)2
Also called Steatite
About it
Soapy to the touch and the softest mineral on the Mohs scale, scratched by a fingernail; pearly foliated masses form in altered ultramafic rocks, and massive soapstone is carved.
- Type
- Mineral
- Group
- Silicate (phyllosilicate), talc group
- Formula
- Mg3Si4O10(OH)2
- Hardness (Mohs)
- 1
- Specific gravity
- 2.58–2.83
- Streak
- white
- Lustre
- pearly, greasy
- Crystal system
- Monoclinic
- Colours
- white, pale green, grey, brown, colourless
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- perfect in one direction, flexible but not elastic flakes
Typical values: real specimens vary. For more, see mindat.org.