All About the Aquamarine
What are Aquamarines?
The lovely Aquamarine (chemical composition: Be3 Al2 SiO6) is part of the Beryl family - a group of durable minerals found the world over. Long reknowned for its beauty, the Bible describes the wheels of God's throne as having the appearance of "gleaming Beryl" (Ezekiel 1:16). The aquamarine, a clear or transluscent light blue-green gemstone, gets its name from the Roman words for "Sea Water", due to its resemblance to a serene, blue ocean.
Other members of the Beryl family commonly used for jewelry are the Emerald and the rarer, pink Morgonite. Red, golden and yellow-green (Heliodor) varieties of beryl are also to be found. The differences in color are caused by impurities - pure Beryl is colorless and known as Goshenite.
Geological Properties of the Aquamarine
Aquamarine (Beryl) crystals occur as transparent to transluscent hexagonal (six sided) prisms. The ends of the crystals are pincoid, meaning made up of multiple pyramidal faces, sometimes to the point that they almost appear rounded. The faces (flat sides) of the crystals tend to be somewhat rough - striated (lined) lengthwise and pitted. Raw aquamarine has a vitreous (glass-like) luster. Small microscopic inclusions are common, however large, visible flaws in aquamarine gem stones are rare and would make the stone susceptible to fracture.
Aquamarines and other forms of Beryl have a hardness of between 7.5 and 8 on the Mohs scale - this is a little harder than gems in the quartz family (i.e. smoky/rose quartz, amethysts, onyx and citrine) but a little softer than the topaz, sapphire or ruby. It has a specific gravity (a measure of the mineral's density) of 2.6-2.9 - a little heavier than quartz gemstones.
The natural color of the aquamarine can be made permanently darker by applying heat of around 750 fahrenheit. Heating to more than 800-850 degrees fahrenheit will discolor the stone.
Origin - Where Aquamarines are Found
Main countries where the aquamarine is found include Brazil, Russia (Siberia), Africa (Madagascar, Tanzania, Kenya and Nigeria), Pakistan, the USA (Colorado) and in parts of Asia. It is frequently found growing in deposits of granite (quartz, feldspar, mica and/or calcite) and is often surface-mined.
Brazilian aquamarines are among the finest produced anywhere in the world. Beautiful, deep blue Aquamarines come from the Santa Maria de Itabira mine in Brazil. These are known as Santa Maria aquamarines. Aquamarines of a similar color are also found in Mozambique and are known as Santa Maria Africana gems.
Other Brazilian aquamarine varieties of note include the uniquely-colored Martha Rocha and Espirito Santo stones.
Another sought-after variety of aquamarine are the exquisitely-colored, light to dark-blue Haramosh gemstones, mined in the Karakoram mountain range in Pakistan.