Appendix B reprises some common minerals. The crystal structure is one of the most important clues to identification. Mineral identification is not hard, but takes some practice. One looks at Moh's hardness, streak, luster, and specific gravity. Additional tests like taste, feel, acid effervescence, or magnetic susceptibility are sometimes useful.
Some minerals are fluorescent.
Both of these are essential to define a mineral. The arrangement of the atoms determines the crystal structure. The table below gives examples from the most common group of minerals, the silicates. For example, quartz is SiO 2 because all four Oxygen atoms connect to adjacent tetrahedra.