Talc is a magnesium mineral, commonly found in metamorphic rocks, such as chlorite schists, serpentine and magnesite. It is monoclinic, crystals are tabular, has a hardness from 1 to 2.5, SG of 2.6 to 2.8, is generally green, white or gray in color. It can also be yellowish or reddish brown. There are several types of talc, , Foliated Talc (hardness of 1, soapy or greasy feel), Stealite or Soapstone (massive, generally inpure, hardness of 1.5 to 2.5, gray to greenish in color and occurs in large deposits)and French Chalk (soft compact white masses.used as chalk in clothing industry for marking fabrics). The talc in the photo is soapstone. Talc is used commercially because of its fragrance retention, luster, purity, softness, and whiteness. Other commercially important properties of talc are its chemical inertness, high dielectric strength, high thermal conductivity, low electrical conductivity, and oil and grease adsorption. Major markets for talc are ceramics, paint, paper, and plastics. ** ** Uses of talc from USGS