Mariposite is a mineral which is a chromium-rich variety of mica, which imparts an attractive green color to the generally white dolomitic marble in which it is commonly found. It was named for Mariposa, California, though it can be found in several places in the Sierra Nevada mountains. It is also found in Marblemount, Washington in the North Cascades. It is also found in a few locations in Newfoundland, Canada, where it is called virginite, and in Europe.
The term "mariposite" also refers to the stone in which the green mica is found. This stone is metamorphic rock, containing varying amounts of dolomite and quartz. Larger proportions of quartz give it a more attractive, translucent appearance. It is used as a decorative construction material, in walls, monuments, and bridges. It is also made into jewelry.
The chemical formula of mariposite is K(Al,Cr)2(Al,Si)4O10(OH)2.