Again, the superscript indicates the extra negative charge. We also encounter groups of atoms that have an overall charge. Minerals have unique physical properties and are pure substances. You should know the six main groups of silicate minerals, along with their basic structures. The rest contain various ions, as indicated above.
Feldspars are the most abundant minerals in the earth s crust.
While you do not need to memorize the formulas for specific minerals, you should also be able to recognize the class of nonsilicate mineral from a given formula. Physical Properties of Minerals Mineral properties fall into three general categories 1. Note that color is a very unreliable indicator of the identity of a mineral. Streak - color of a mineral in its powdered form. The important thing to know about density is that things of less density float on things of greater density .