While we traditionally think of Garnets as deep red in color, the Demantoid variety is a vibrant green gemstone composed of the mineral andradite and rich in calcium and iron. First discovered in Russia in the 1800s, Demantoid Garnets are treasured gems first made famous by Russian jeweler Fabergé. They are relatively rare—especially stones over 3 carats—and prone to inclusions, which are, uniquely among gems, considered a valuable aesthetic property in this stone. Gems with “horse-tail” inclusions are especially sought-after. Such inclusions are caused by the presence of byssolite, a form of asbestos, and are considered proof of the gem’s origin in Russia’s Ural Mountains.