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
Reinerite Reinerite Reinerite is a rare arsenite (arsenate(III)) mineral with chemical formula Zn(AsO). It crystallizes in the orthorhombic crystal system. Reinerite is most commonly found as a sky blue colored mineral, however, it may also be a light yellowish green color. Reinerite has a relative hardness of 5 to 5.5 on the Mohs Scale which is equivalent to that of a knife blade and or shard of glass. It has a density of 4.27 g/cm, and it exhibits a nonmetallic luster that may be described as glassy or vitreous. Reinerite develops in dolostone-hosted locations. It is known especially from Namibia, Africa,