Where Does Phlogopite Come from?

Phlogopite micas are found primarily in igneous rocks, although it is also common in contact metamorphic aureoles of intrusive igneous rocks with magnesian country rocks and in marble formed from impure dolomite (dolomite with some siliclastic sediment).

How is phlogopite formed?

Phlogopite is usually found in metamorphic rocks. An ideal condition for phlogopite formation is when a dolomitic limestone or a magnesium-rich limestone, with some clay content, is subjected to hydrothermal metamorphism. ... These include ultramafic rocks such as peridotite, kimberlite, lamproite, and serpentinite.

What mineral group is phlogopite?

Phlogopite, also called brown mica, basic aluminosilicate of potassium, magnesium, and iron that is a member of the common mica group. Varieties that contain only small amounts of iron are economically important as electrical insulators.