Uvarovite, which is composed of Calcium Chromium Silicate, is classified as a nesosilicate member of the garnet group. It is a very attractive bright emerald green color, a property that is caused by the presence of chromium. It is formed by the metamorphosis of chromium bearing siliceous limestones. Crystalline versions usually have either 12 or 24 faces — the better examples are used as unusual gemstones. It also occurs as granular and massive forms, often in association with the minerals chromite, and serpentine. All three types are popular with collectors as mineral specimens.