Chemical composition: Mg3Si4O10 (OH) 2. Ti, Ni, Fe and Mn may substitute for Mg.
(i) Form: Tabular, fine-grained massive with foliaceous structure or massive granular
(ii) Colour: White, gray, apple-green.
(iii) Lustre: Resinous, pearly, and greasy.
(iv) Streak: White.
(v) Hardness: 1, marks on a cloth.
(vi) Cleavage: Perfect 1 set.
(vii) Fracture: Subconchoidal to uneven.
(viii) Specific gravity: 2.7 – 2.8.
(ix) Diaphaneity: Transparent to translucent.
(ix) Feel: Greasy, soapy.
(x) Tenacity: Sectile
The most common use is in talcum powder. Talc is also used as slabs on laboratory tabletops in switchboards, paint, ceramic, rubber, insecticide, roofing, paper and foundry facings.