Chromium-Dravite

chromium-dravite

phengite

taeniolite

muscovite

Images

Formula: NaMg3Cr6(Si6O18)(BO3)3(OH)3(OH)
Cyclosilicate (ring silicate), borosilicate, tourmaline group
Specific gravity: 3.4
Hardness: 7 to 7½
Streak: Greyish green
Colour: Dark emerald-green to greenish black
Common impurities: Mn,Ti,V,Al,V,Ca
Environments

Metamorphic environments

Localities

At the first recorded locality, the Velikaya Guba Deposit, Zaonezhie peninsula, Medvezhyegorsky District, Republic of Karelia, Russia, chromium-dravite occurs in micaceous metasomatites, associated with chromium-bearing phengite, tainiolite, vanadium-bearing muscovite, quartz and dolomite (AM 69.210).

Back to Minerals