Description
The mineral mariposite is an unofficially recognized chromium-bearing variety of phengite, a muscovite with high silica content. The chemical formula of the potassium-aluminum-chromium silicate is K(Al,Cr)2(Al,Si)4O10(OH)2. This phyllosilicate belongs to the micas. Mariposite is a green mica, with its green color due to the element chromium. Like other micas, mariposite is flaky and has a low average density. A rock composed primarily of the mineral mariposite is also called mariposite. The mineral mariposite is named after the place where it was first discovered, Mariposa, California. The mineral and rock mariposite occurs primarily in dolomitic marbles. The type locality is Mariposa in the United States, but it is also found in Canada and Europe.
