Multi-colored Tourmaline crystals above a Lepidolite covered base. emerald-green tips that evolve into a bluish-green coloration which then changes over to a lighter green near the bottom. The lower portion of the actually becomes "watermelon" in that the
Gem quality sphalerite is a rare collector stone. The mineral is usually nearly black in color but is occasionally found in transparent pieces of an orange or yellowish brown hue. Clean pieces are extremely rare.
A variety of Chrysoberyl, alexandrite is pleochroic, which means it changes color depending on the angle at which it is viewed. Its color-changing property is due to an exceedingly rare combination of minerals that includes titanium, iron and chromium.
Diamonds are a hard crystalline form of carbon. These uncut diamonds are from the Russian State Precious Metals and Gemstones Collection Fund, part of the Russian Finance Ministry. Photographed in Moscow, in March