Emerald and aquamarine are by far the most popular varieties of gem beryl; however, the popularity of morganite has surged. Beryl is a mineral that contains a significant amount of beryllium. Beryllium is a very rare metal, and that limits the formation of beryl to a few geological situations. Pure beryl has no color and is known as “goshenite,” but transparent crystals with inclusions and impurities are different colors and are known as gemstones with different names.  Colors range green to blue to red, yellow, and white. Green beryl is caused by traces of chromium.