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
Mohs surgery for uncomplicated, non-melanoma skin cancer of less than one centimeter in size. On these parts of the body, the risks exceed the benefits of the procedure. Due to high risk of recurrence among other reasons, Mohs surgery could be considered for skin cancers on hands, feet, ankles, shins, nipples, or genitals. In 2012 the American Academy of Dermatology published appropriate use criteria (AUC) on Mohs micrographic surgery in collaboration with the following organizations: American College of Mohs Surgery; American Society for Mohs Surgery; and the American Society for Dermatologic Surgery Association. More than 75 physicians contributed to the development of