Mineral necessarily constant for all sides, which is a function of its structure; crystallographic weakness renders some directions softer than others. An example of this property exists in kyanite, which has a Mohs hardness of 5½ parallel to [001] but 7 parallel to [100]. The most common scale of measurement is the ordinal Mohs hardness scale. Defined by ten indicators, a mineral with a higher index scratches those below it. The scale ranges from talc, a phyllosilicate, to diamond, a carbon polymorph that is the hardest natural material. The scale is provided below: Lustre indicates how light reflects from the mineral's
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