In rocks, some mineral species and groups are much more abundant than others; these are termed the rock-forming minerals. The major examples of these are quartz, the feldspars, the micas, the amphiboles, the pyroxenes, the olivines, and calcite; except the last one, all of the minerals are silicates.
Overall, around 150 minerals are considered particularly important, whether in terms of their abundance or aesthetic value in terms of collecting