amethyst is a violet variety of quartz. the name comes from a greek word, a refered to the belief that the stone protected its owner from drunkenness. the ancient greeks wore amethyst and carved drinking vessels from it in the belief that it would prevent intoxication.
Aquamarine, named for the Latin phrase "water of the sea", is the blue to blue-green variety Beryl. Beryl also contains other gem varieties, including Emerald, and some lesser known varieties such as Morganite and Heliodor.