Mineral Type - Mtorolite / Chrome Chrysophrase

Formula: SiO2

A variety of chalcedony colored deep green by Cr compounds. (Compare with the more common Chrysoprase variety of chalcedony, which is colored by nickel.) Chrome chalcedony found in an ancient Roman gem collection may have come from one of the chromium deposits in what is now Turkey. Present commercial production comes from Zimbabwe under the trade name "mtorolite", and from Bolivia under the trade name "chiquitanita".