Aquamarine
The variety of beryl whose name literally means "water blue" in Latin. It comes in all the irresistible colors of the sea - from light blue to bluish green to greenish blue to deep blue. It is the birthstone for March.
Fine aquamarines are valued for their pure tone of color, crisp transparency and brilliant internal reflections. Aquamarine is often heated to remove the yellow color components and leave a pure blue, but it is the intensity and clarity of color that establishes value, not the specific hue. American consumers tend to prefer bluer gems that have likely been heated, while Europeans tend to prefer greenish-blue (seafoam) varieties that have likely not been heated. Both are equally valuable. Aquamarines are a durable gem and are appropriate for any kind of setting.
