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 sections are examined instead of the Mohs paste-fixed sections. This method is now commonly referred to as Mohs surgery, and occasionally "chemosurgery", in reference to the Mohs paste that Mohs initially used. In 1943 Mohs married Mary Ellen Reynolds, who died in 1995. Mohs died at his home in Madison, Wisconsin on 2 July 2002, at the age of 92. He was survived by two sons, Frederic and Thomas, of Madison; and a daughter, Jane Schimming of Stuart, Fla. Frederic E. Mohs Frederic Edward Mohs (1 March 1910 – 2 July 2002), a physician and general surgeon, developed the Mohs