This chromium diopside crystal is from the Merelani Hills in the Lalatema Mountains, Simanyara District, Manyara Region, Tanzania. There are several mines that are famous for their tanzanite production. This gem bearing area contains 46 mineral species including chromium diopside, It is a silicate that contains the elements Ca, Cr, Mg O and Si.. This crystal is translucent to transparent with a glass luster. It has minor graphite matrix attached. It measures 21 x 13 x 8 mm.