Final answer:
Silicate subgroups encompass minerals such as feldspars, quartz, and mica, as well as olivine, pyroxene, and amphibole. They are identified based on cleavage, color, and crystal form and are abundant in various rock types like granite, gabbro, and basalt. Metamorphic rocks may include minerals like garnet and members of the aluminosilicate group.
Step-by-step explanation:
The different silicate subgroups include a variety of minerals with diverse chemical compositions and structures. Examples of these minerals are:
- Feldspars, including orthoclase (K-feldspar) and plagioclase feldspars, which are very common in the Earth's crust and can be identified by their cleavage and color variations.
- Quartz, known for its irregular, glassy grains and lack of cleavage, making it distinct among minerals.
- Mica minerals like muscovite and biotite, which have perfect cleavage in one direction and can appear in flakes or layers.
- Olivine, pyroxene, and amphibole are typically found in rocks such as peridotite, basalt, and gabbro and can be distinguished by their crystal forms and angles of cleavage.
Some rocks will contain these minerals in varying quantities based on their classification as ultramafic, mafic, or felsic. Minerals like garnet, andalusite, sillimanite, kyanite, staurolite, and cordierite are also important silicate minerals that might be encountered during the study of metamorphic rocks.