This tremolite crystal is from the Merelani Hills (Merelani Gem Mining Area) in the Lalatema Mountains, Simanjiro District, Manyara Region. Tanzania.This area contains 46 different mineral species including tremolite. It is an amphibole containing the elements Ca Mg Si O and H. Crystals are colorless in pure from and are colored, in this case by chromium (Cr), by trace elements in the crystal lattice. This is a translucent crystal, under bright light, with a rich green color and a bright glass luster. It is double terminated and has some minor graphite and quartz matrix on the rear side It measures 1 1/4 x 3/4 x 3/8 inches or 32 x 19 x 10 mm. It weighs 37 carats..