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
Reinerite Reinerite Reinerite is a rare arsenite (arsenate(III)) mineral with chemical formula Zn(AsO). It crystallizes in the orthorhombic crystal system. Reinerite is most commonly found as a sky blue colored mineral, however, it may also be a light yellowish green color. Reinerite has a relative hardness of 5 to 5.5 on the Mohs Scale which is equivalent to that of a knife blade and or shard of glass. It has a density of 4.27 g/cm, and it exhibits a nonmetallic luster that may be described as glassy or vitreous. Reinerite develops in dolostone-hosted locations. It is known especially from Namibia, Africa,