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The Gemstone Aquamarine

Aquamarine, named for the Latin phrase "water of the sea", is the blue to blue-green variety Beryl. Beryl also contains other gem varieties, including Emerald, and some lesser known varieties such as Morganite and Heliodor. Aquamarine ranges in color from a faint light blue to blue and bluish-green, with lighter colored stones being the more common type. Light green Beryl can be transformed into Aquamarine if heated to 750º F (400º C). The green hues in most Aquamarine can also be removed through heat treatment.

Color

Blue

Hardness

7.5 - 8.0

Chemical Formula

Be₃Al₂Si₆O₁₈

Mineral Class

Beryl (Aquamarine)

Additional Properties

Crystal System
Hexagonal

Refractive Index
1.57 - 1.58

Double Refraction
.006

Transparency
Transparent to translucent

SG
2.6 - 2.8

Luster
Vitreous

Cleavage 3,1 - basal

All About

Aquamarine is a relatively common gemstone, and is affordable in lighter colors. Deeper colors can command high prices. Some enormous transparent crystal masses of Aquamarine have been found, and exquisite gems weighing thousands of carats have been cut from them.

The light blue to blue-green color of Aquamarine may fade upon prolonged exposure to light, so it is especially important to purchase this gem from a reliable dealer. Aquamarine is a hard and durable gem, but it may develop internal cracks if banged hard.

Light blue Topaz is easily mistaken for Aquamarine. The colors of these two gems can be identical, and their physical properties are very similar. Topaz is generally less expensive, and some fraudulent dealers may sell their Topaz as Aquamarine.

Unlike Emerald, Aquamarine gems are often completely flawless. Aquamarines with visible flaws are rarely seen. The costs of producing synthetic Aquamarine are very high when compared to the relative abundance of this gem, so synthetic Aquamarine is generally not produced for the gemstone market.

Uses

Aquamarine is faceted into many cuts. It is a popular stone for rings, earrings, necklaces, and other jewelry forms. Many exceptionally large and flawless Aquamarine gem pieces have been cut. Occasionally, perfect, flawless, six-sided crystals are worn as necklace pendants. Translucent Aquamarine displaying cat's eye effect and asterism are uncommon, but they do exist and are cut and polished into cabochons. Lesser quality Aquamarines lacking good transparency are sometimes used as beads and as rough polished stones in bracelets and necklaces.

Aquamarine is the birthstone of March.

Varieties

Cat's Eye Aquamarine - Aquamarine displaying a cat's eye effect.

False Names

Brazilian Aquamarine - May refer to Aquamarine that originates in Brazil, but often is used as a false name for blue Topaz.
Mass Aqua - Faceted glass that is dyed blue to resemble Aquamarine.
Nerchinsk Aquamarine - False name for blue Topaz.
Siam Aquamarine - False name for heat treated blue Zircon.

Treatments & Enhancements

Most Aquamarines on the market are heat treated. Natural Aquamarine is is usually lighter and more greener in color, and heat treatment creates deeper bluer hues. While natural deeper bluish hues do exist, they are uncommon. The gemstone industry considers it an acceptable practice to heat treat Aquamarines, although this information should always be disclosed to the buyer.

Aquamarine Sources

Brazil is the largest producer of gem Aquamarine; other important producers are Pakistan, Myanmar (Burma), Russia, China, Namibia, Mozambique, Zambia, Kenya, and the United States (Colorado and California).