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Aquamarine Gemstone Information

Aquamarine is a light blue to dark blue and sea green variety of Beryl. Most material has high transparency and clarity giving light coloured stones a very bright appearance. The name aquamarine means 'Sea Water' in Latin and describes the colour that was most popular in the past (bluish-green). The most popular colour in recent times is blue, hence greenish stones are often treated to remove the green component. There are those who still favour the natural colour of the sea green stones believing them to more characteristic of aquamarine.

Although most aquamarine occurs naturally with high clarity, some have oriented tube-like inclusions that resemble rain; these inclusions help to identify aquamarine and other beryls.

Emerald is also a variety of Beryl, with a distinctive grass green colour that distinguishes it from the sea green colour of aquamarine and light green precious beryl. Aquamarine and light green precious beryl is coloured by iron, whereas emerald is coloured by chromium or vanadium.

Aquamarine is mined in many parts of the world, deposits are found in: Africa (Namibia, Nigeria, Zambia, Zimbabwe), Australia (Queensland), Brazil (a major source, Minas Gerais, Espirito Santo and Bahia), Canada, China, India, Kenya, Madagascar, Myanmar, Russia (Ural mountains), Sri Lanka, Tanzania, the USA (Colorado and many other locations) and Vietnam.

Physical Properties

Stone type:
A variety of the species Beryl
Crystal System:
Hexagonal
Chemical Composition:
Aluminium Beryllium Silicate, Be3Al2(SiO3)6
Colour:
Light blue to sea green, it may be blue-green or green-blue in light or darker shades.
Aquamarine is coloured by iron.
Lustre:
Vitreous
Pleochroism:
Dichroic: distinct, seen as blue or green and colourless
Dispersion:
Low
Hardness:
71/2 - 8 on the Mohs' scale.
Toughness:
Fair
Cleavage:
Very imperfect
Density in gm/cc:
2.68 to 2.74
Double refraction:
Yes
Refractive index:
1.564 - 1.596

Common Treatments

Blue aquamarine is now considered the most valuable, hence blue stones with a slight green or yellow tint are heated to remove the unwanted tint.

Some blue material is produced by heating pure green or yellow-green stones.

Some cutters and dealers prefer the natural sea green colour of aquamarines to the modified colours that follow treatment. They feel that natural untreated stones should be sold at a premium.


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