Fuchsite is a green variety of muscovite mica. It differs from most other muscovite by having a variable amount of trivalent chromium substituting for aluminum within the mineral. Chromium is the source of fuchsite’s green color.
Occasionally, corundum crystals are found in fuchsite. When these corundum crystals are of a bright red color, the material is known as ruby in fuchsite. This material attracts a lot of attention at rock, mineral, gem, and lapidary shows because of the contrasting colors of the fuchsite and ruby, and because the corundum crystals often exhibit spectacular hexagonal shapes when cut in slabs, cabochons, spheres, and other objects.