Aquamarine is the name used for the mineral beryl within the color range of greenish blue to blue. Beryl was once one of the world’s only important ores of beryllium metal. However, the extraction of beryllium is very expensive. These days, small amounts of beryl are a by-product of gemstone mining. Aquamarine gemstones can range from a very light hue to much deeper, vibrant shades of blue. The term aquamarine is derived from a combination of two Latin words. The first one, aqua, means water and the second, marina means sea. Together, the word translates to the color of the sea. Aquamarine is not classified as a precious stone.
Occurrence and Mining
Brazil is the world’s leading source of gem-quality aquamarine for over 100 years. It is found there in both pegmatite and alluvial deposits. Afghanistan, Kenya, Madagascar, Malawi, Mozambique, Nigeria, Pakistan, Russia, Tanzania, and Zambia are all sources of aquamarine. India and Sri Lanka have long histories of aquamarine production from alluvial deposits. Aquamarine has been found at many locations in the United States. To date, almost all of the production has been from small-scale mining, often where multiple minerals are being produced. Most gem-quality aquamarine crystals form in cavities below Earth’s surface during the late stages of a magma body’s crystallization. The cavities provide open space for crystals to grow. The slow underground cooling rate provides the time needed for the development of large crystals. And, the late-stage timing provides the fluids and a supply of the beryllium needed to form beryl, a beryllium mineral. Aquamarine is usually found in granite pegmatites. Another source is from veins in metamorphic rocks that were mineralized by hydrothermal activity. If rocks containing aquamarine are exposed by weathering and erosion, the exceptional hardness of aquamarine (7.5 to 8 on the Mohs scale) will cause it to persist in overlying soils and stream sediments. Much aquamarine has been produced from stream sediments. Where it is found in stream sediments suggests that a primary deposit is located upstream.
The price of aquamarine is mainly determined by weight and the strength of its color. Gems with a faint blue color are abundant and inexpensive. Gems with a rich blue color are much more expensive because rich color in aquamarine is very rare. A small aquamarine with a rich blue color will cost a lot more than identical-size stones with a faint blue color.
Greenish blue to blue (color almost always has been improved by heat treatment)
Colorless (harder than the streak plate)
Translucent to transparent
2.6 to 2.8
Crystals are prismatic, often with flat terminations, hexagonal, and without striations. Hardness and relatively low specific gravity.
Hexagonal (often occurs in prismatic to tabular crystals with a hexagonal cross section)
Aquamarine has a hardness and durability that makes it suitable for all jewelry uses.
7.5 to 8