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
Mineral Point, Wisconsin county seat of Iowa County was relocated to nearby Dodgeville, Wisconsin, where it remains today. Afterwards there was an intense rivalry between the two cities, during which Mineral Point fired a cannon towards Dodgeville's direction. As lead mining declined in Mineral Point, zinc mining and smelting became important new industries. Zinc ore was discovered with increasing frequency near the bottoms of old lead mines. The Mineral Point Zinc Company was founded in 1882, and by 1891 it was operating the largest zinc oxide works in the United States at Mineral Point. Zinc mining and processing continued on a large scale