Mineralogy classified into density (often given as specific gravity); measures of mechanical cohesion (hardness, tenacity, cleavage, fracture, parting); macroscopic visual properties (luster, color, streak, luminescence, diaphaneity); magnetic and electric properties; radioactivity and solubility in hydrogen chloride (). "Hardness" is determined by comparison with other minerals. In the Mohs scale, a standard set of minerals are numbered in order of increasing hardness from 1 (talc) to 10 (diamond). A harder mineral will scratch a softer, so an unknown mineral can be placed in this scale by which minerals it scratches and which scratch it. A few minerals such as calcite and kyanite
Frederic E. Mohs Frederic E. Mohs Frederic Edward Mohs (1 March 1910 – 2 July 2002), a physician and general surgeon, developed the Mohs micrographic surgery (MMS) technique in 1938 to remove skin cancer lesions while still a medical student at the University of Wisconsin–Madison. The Mohs procedure is considered the best method for treating certain types of skin cancer, because it has very high cure rates for even high-risk lesions, combined with maximal preservation of healthy tissues. Mohs was born in Burlington, Wisconsin. His father died when he was 3 months old, and the family moved to Madison, where his mother ran