Aquamarine is the sky blue or sea blue variety of beryl, sometimes it is sea green,
a variety considered less desirable. The word aquamarine literally means seawater and is often
simply referred to as aqua.
Coloration
The color of aquamarine is due to the presence of traces of iron present as an impurity in the
crystal structure of beryl.
Enhancement Techniques
As with many gemstones, the color of aquamarine has almost always been improved by treatment
of some kind. Heat treatment is used for aquamarines, to turn greenish, yellow or brown stones
into a beautiful blue. The stones are heated to about 400 to 450 degrees Celsius, and the color
change is permanent. Enhancements of any type in any gemstone should always be reveal by your
jeweler.
Color Saturation & Size
Even the best aquamarines are fairly pale compared with other gemstones such as sapphire.
Large stones benefit from the effects of color saturation, and as aquamarine, unlike emerald,
tends to form quite large clear crystals, this means that large aquamarines are relatively easy
to find, and the price does not rise so steeply with size as it does with many other stones. It
also means that small stones often lack color intensity and are therefore not as attractive.
Small aquamarines with good color are therefore harder to obtain, and relatively expensive for
their appearance.
Durability
Aquamarine is reasonably hard, having a hardness of 71/2 to 8 on Moh's scale, compared with 10
for diamond, 9 for corundum, and 8 for topaz. Hardness is generally a desirable feature is
gemstones.
Pricing
The price range of aquamarine is quite large, ranging from a few dollars for small pale stones
to several thousand for larger, deeper color more intense stones.
Technical Characteristics
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Chemical Composition:
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Be3Al2(SiO3)6 - Beryllium Aluminium Silicate
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Hardness:
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7.5 - 8
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Specific Gravity:
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2.68 to 2.73
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Refractive Index (R.I.):
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1.570 - 1.586
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Bi-refringence:
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0.005 to 0.006
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Optic Sign:
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Negative
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Optical Character:
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Uniaxial
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Crystal Structure:
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Hexagonal
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