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 was largely unsuccessful, as many surgeons were not comfortable learning skin pathology and laboratory techniques. Dermatologists, who are well trained in dermatopathology, and who treat skin cancers on a daily basis, quickly embraced the procedure. Today, most Mohs procedures are performed by dermatologists, although a small number of plastic surgeons, otolaryngologists, and pathologists are also practicing and using the procedure as well. Mohs' technique was later modified by Perry Robins in the 1970s, using fresh-tissue frozen histology. Rather than using the anesthetic Mohs paste, local anesthetic is used. The fresh skin specimen is then mounted on a cryostat, and frozen