Aquamarine is in fact a color variety of the mineral beryl (emerald is another). Like many beryls, aquamarine forms large crystals suitable for sizable fashioned gems and carvings. It’s preferred color is a moderately strong dark blue to slightly greenish blue. (Another plus: it has been said that the mineral beryl gives the wearer protection against foes in battle or litigation. It makes the wearer unconquerable and amiable, and also quickens the intellect.)
If you were born in March, these seem like pretty good reasons to get yourself some aquamarine! Unconquerable happiness and amiability to all!
As always, the Gemological Institute of America gets credit for all of the information here. I just copy & paste.
The name comes from the Latin for seawater, and it was said to calm waves and keep sailors safe at sea. March’s birthstone was also thought to enhance the happiness of marriages (it’s also the gem of the 19th wedding anniversary). The best gems combine high clarity with limpid transparency.