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 made of zinc chloride and bloodroot (the root of the plant "Sanguinaria canadensis", which contains the alkaloid sanguinarine). The original ingredients were 40.0 g Stibnite, 10.0 g Sanguinaria canadensis, and 34.5 ml of saturated zinc chloride solution. This paste is similar to black salve or "Hoxsey's paste" (see Hoxsey Therapy), a fraudulent patent medicine, but its usage is different. Hoxsey used the paste for long periods, a harmful practice that was rapidly discredited. Mohs left the paste on the wound only overnight, and the following day, the cancer and surrounding skin would be anesthetized and the cancer removed. The specimen