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
American College of Mohs Surgery American College of Mohs Surgery The American College of Mohs Surgery (abbreviated as ACMS) is a membership-based organization of surgeons who are fellowship-trained in Mohs surgery, a technique that removes skin cancer in stages, one tissue layer at a time. Its president for 2015-16 is John G. Albertini. The ACMS is both the oldest and largest professional membership organization for Mohs surgeons. The American College of Mohs Surgery was established in 1967 by Frederic E. Mohs, a general surgeon based at the University of Wisconsin – Madison. In addition to founding the College, Mohs also served as its first president.