What is the composition of talc?

Talc is a metamorphic mineral that consists of hydrated magnesium silicate. More commonly known as soapstone, talc is a soft rock that is easy to shape and has been widely used to make decorative and practical objects for thousands of years.

Talc deposits frequently occur in the metamorphic rocks located along convergent plate boundaries. Talc forms when water containing dissolved magnesium and silica is heated and begins to react with dolomitic marbles. Minerals such as serpentinite or dunite, that have been altered by chemical active fluids and thermal energy, may also form talc. Talc is a translucent mineral that may appear white, gray, green or brown in color.