Two of the most well known gemstones are from the Beryl family, Emerald and Aquamarine. Some other lesser known Beryl stones are Heliodor (yellow or golden yellow), Goshenite (colorless), Morganite (pink, rose, peach or violet colored) and Red Beryl.
Beryl (Beryllium aluminium silicate) has a hardness of 7.5 on the Mohs scale. (Diamond is the hardest gemstone with a hardness of 10). It has a hexigonal structure, or is six-sided.