Goshenite
Although impurities in beryl create a variety of gemstones, you can also find beryl in crystal form that has no impurities, a gem called goshenite. Just like all beryl stones, goshenite is made up of beryllium, aluminum, silicon and oxygen, but since goshenite lacks iron, chromium or manganese, it is colorless. Goshenite can sometime be found wrapped in green foil, to resemble an emerald, and it can be irradiated to turn it into heliodor.
Aquamarine
After emerald, aquamarine is probably the best known of all the beryl gemstones. Aquamarine is created by iron (Fe) impurities in the beryl crystals. The Fe 2+ ions in the crystal structure create a blue tint, while the Fe 3+ ions produce a yellow tint. The relative combination of Fe 2+ and Fe 3+ create the blue to blue-green color of aquamarine.
Heliodor
Heliodor includes all varieties of beryl crystals that have a yellow, yellow-green, green, orange, brown and golden color. Heliodor occurs when iron is present in a beryl crystal, just like aquamarine, except there is little to no Fe 2+ present, making the color lack the blue hues of aquamarine. Heliodor that is pure yellow or golden in color is generally referred to as golden beryl.
Red Beryl
Red Beryl, sometimes called bixbite, is formed when manganese ions are present in the beryl crystal structure. Red beryl refers to only beryl crystals that are a deep or pure red, as light red or pink beryl crystals have a different name. Much like Fe 2+ ions create the blue color for aquamarine, the Mn 2+ ion creates the deep red color for red beryl. Red beryl is fairly rare, found in only a few locations in the western U.S. and Mexico.
Morganite
Morganite refers to beryl crystals that contain both manganese and iron ions. The combination of red manganese and yellow iron creates a range of colors from pink to peach to orange. Morganite is very rare and is mined in only three places, California, Brazil and Madagascar. The New York Academy of Sciences named the gemstone after banker J.P. Morgan, who was an avid gemstone collector.