The name derives from the Latin expression for seawater. Aquamarine is a member of the beryl family and is known for its delicate blue or blue green coloring, which accounts for its name. Aquamarine is the birthstone for March. Aquamarine is a popular stone with very good hardness and luster.
Like seawater, aquamarine comes in blue and green blue color. The more saturated the color, the higher the value, though almost all aquamarine has a light tone.
Aquamarine is colored by trace amounts of iron that find their way into the crystal structure. A saturated blue is the most desired color.
Aquamarines of the best quality are clear, transparent gems. Some gems can carry inclusions of long, hollow rods, a trademark of the beryl family. Aligned traces of foreign minerals, a rare feature, cause a cat’s eye effect or star effect (asterism) with six rays in a vivid sheen. Cat’s eye aquamarine and star aquamarine usually command premium prices.
The favored cuts are emerald (step) and brilliant cut with long or rectangular shapes. Turbid stones get a cabochon cut.
Aquamarine location and deposits
The leading producer of aquamarine is Brazil, with many mines spread throughout the country. Other deposits found in Australia, Myanmar (Burma), China, India, Kenya, Madagascar, Mozambique, Namibia, Nigeria, Pakistan, Zambia, Zimbabwe, as well as in several U.S. locations.
Common Aquamarine treatments
Most aquamarines have been heat treated to produce the popular blue-green colors from less desirable yellow or pale stones. Lower quality stones are heated to 725-850 degrees F (400-450 degrees C) in order to change the color in favor of the desired, permanent aquamarine blue. Higher temperatures would result in discoloration.
There have been huge finds of aquamarine with the weight of several tons that didn’t qualify for cutting due to the weak, gray or opaque color. The largest find of aquamarine in gemstone quality dates back to 1910. The “Minas Gerais” in Marambaya, Brazil mined a stone of 243 lb (110.5 kg), 18 inch (48.5 cm) long and 15.5 inch in diameter that was cut in many gems of a total weight of more than 100,000 ct.
The ‘Dom Pedro’, weighing 26 kg and cut in Idar-Oberstein/Germany in 1992 by the gemstone designer Bernd Munsteiner, made it the largest aquamarine ever to have been cut.
Color: Light blue to dark blue, blue green
Chemical composition: Al2Be3Si6O18, aluminum beryllium silicate
Crystal system: (Hexagonal), hexagonal prisms
Hardness: 7.5 – 8 (Mohs scale)
Specific gravity: 2.68 – 2.74
Refractive index: 1.564 – 1.596
Birefringence: -0.004 to – -0.005
Color of streak: White
Absorption spectrum: 537, 456, 427
The Aquamarine zodiac, myth & legend
According to the saga the aquamarine originated in the treasure chest of fabulous mermaids, and has, since ancient times, been regarded as the sailors’ lucky stone. Aquamarine is the birthstone for those born in March.
In Antiquity, as well as in the Middle Ages people believed that the cosmos is reflected in gemstones. No surprise that aquamarine is assigned to planet Neptune. The esoteric movement revived the ancient belief and the gem industry made it another marketing tool to promote certain gems.
The healing powers of gems remain a controversial issue, but are mentioned for centuries by healers, shamans and medicine men. Whether its factual or a placebo effect doesn’t matter, if it helps. The safest approach is to wear the gemstone in skin contact to the troubled part of the body. Aquamarine is said to be of help for arthritis, eye inflammation, sore throat and varicose veins.