Chromotremolite - variety of Tremolite (Amphibole) rich in Chromium.
  
From: Merelani Hills, Simanjiro, Manyara, Tanzania.
  
Aggregate of sub-euhedral prismatic Chromotremolite crystals, translucent with a light green color, associated with lamellae of black Graphite with metallic luster and anhedral white Quartz. Sample measuring 4.0 x 3.5 x 1.3cm and 25 grams. Associated with high pressure metamorphic rocks.