Talc Talc Talc or talcum is a clay mineral composed of hydrated magnesium silicate with the chemical formula HMg(SiO) or MgSiO(OH). In loose form, it is (in ratio with or without corn starch) one of the most widely used substances known as baby powder. It occurs as foliated to fibrous masses, and in an exceptionally rare crystal form. It has a perfect basal cleavage, and the folia are not elastic, although slightly flexible. The Mohs scale of mineral hardness, based on scratch hardness comparison, defines value 1 as the hardness of talc. Talc can easily be scratched by a fingernail. Talc
Glauconite Glauconite Glauconite is an iron potassium phyllosilicate (mica group) mineral of characteristic green color with very low weathering resistance and very friable. It crystallizes with a monoclinic geometry. Its name is derived from the Greek "glaucos" ("γλαυκος") meaning 'blue', referring to the common blue-green color of the mineral; its sheen (mica glimmer) and blue-green color presumably relating to the sea's surface. Its color ranges from olive green, black green to bluish green, and yellowish on exposed surfaces due to oxidation. In the Mohs scale it has hardness of 2. The relative specific gravity range is 2.4 - 2.95. It is