muscovite
The most common minerals in gneiss are quartz, potassium feldspar, and sodium feldspar. Smaller amounts of muscovite, biotite and hornblende are common. Gneiss can also form from gabbro or shale.
Mica, Quartz, Iron Pyrite, and Turquoise
Mica comes in a variety of forms and colors. The most common micas are biotite, which is dark colored, and muscovite, which is light in color.
Different varieties of mica will appear in different colors. The two most common varieties are muscovite, which is light in color, and biotite, which appears dark brown or black.
Biotite is the most common form of mica.
muscovite
The most common nonferromagnesian member of the mica family is muscovite.
muscovite
The most common minerals in gneiss are quartz, potassium feldspar, and sodium feldspar. Smaller amounts of muscovite, biotite and hornblende are common. Gneiss can also form from gabbro or shale.
Muscovite
Mica, Quartz, Iron Pyrite, and Turquoise
Decompression and Exfoliation weathering are common in Mica and Shale.
Decompression and Exfoliation weathering are common in Mica and Shale.
Mica.
Mica comes in a variety of forms and colors. The most common micas are biotite, which is dark colored, and muscovite, which is light in color.
Serecite.