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
Mohs surgery spindle cell tumors, sebaceous carcinomas, microcystic adnexal carcinoma, merkel cell carcinoma, Paget's disease of the breast, atypical fibroxanthoma, and leiomyosarcoma. Because the Mohs procedure is micrographically controlled, it provides precise removal of the cancerous tissue, while healthy tissue is spared. Mohs surgery can also be more cost effective than other surgical methods, when considering the cost of surgical removal and separate histopathological analysis. However, Mohs surgery should be reserved for the treatment of skin cancers in anatomic areas where tissue preservation is of utmost importance (face, hands, feet, genitals). Mohs surgery should not be used on the trunk or extremities