Aquamarine (a name meaning sea water) is a blue to bluish-green variety of
beryl. The color is caused by trace amounts of iron in the crystal structure. It
has very good hardness and durability, rating a 7.5 on the Mohs scale.
Aquamarine tends to be found primarily in pastel colors, though it does
sometimes occur in deeper shades. Because aquamarine is not an intensely colored
stone, smaller gems are nearly always lighter colors.
The finest aquamarine is deep blue and is known as Santa Maria. Santa Maria
aquamarine was originally found in Brazil, though more recently the same color
has been found in Mozambique in East Africa. The Mozambique gems are called
Santa Maria Africana (or Santa Maria Afrique) aquamarines to distinguish them
from the Brazilian equivalents. These beautiful top color aquamarines are
extremely rare and difficult to obtain and thus command the highest prices.
Greenish or yellow tinted aquamarine is routinely heat treated at low
temperatures to make it pure blue, though the untreated green and teal stones
are quickly gaining popularity. Because this treatment is undetectable and
permanent, it has no affect on the value.
Aquamarine is the traditional birthstone for March.