Stunning neon green color marks the best of these chromian tremolites. This is rare material is seldom found during mining for the more typical gem species here such as tanzanite and spinel. Tremolite is normally a relatively ugly "rock former" species with grains and frozen fragments in rocks, and which rarely forms crystals of any beauty. These few that attain such a high color saturation are highly sought after. Also, this is a cluster, whereas most we have seen over the years were only single crystals. From the collection of Tim Sherburn, who had a superb suite of rare Tanzanian gem crystals.