Rubies are formed of a mineral called corundum, comprised of aluminum oxide. The red color is caused by traces of chromium. Corundum also forms sapphire in many colors, which generally come from ...

Myanmar’s rich mineral deposits come with a sobering backdrop. Decades of political instability, military control, and human rights abuses cast a shadow over its gemstone trade. Mining practices ...

There are basically three types of crystals: acrylic, mineral glass and sapphire glass. Acrylic crystals are by far the most common. They are inexpensive, shatterproof, widely available and have ...