BERYL-AQUAMARINE

Description:

Aquamarine is the blue-green variety of the mineral beryl. Beryl is one of the most important gem minerals. It is colorless in pure form, but many different impurities give beryl its varied coloration. Without these splendid color varieties, beryl would be a rather ordinary gemstone with only average fire and brilliance. Another well known variety of beryl is emerald, the green variety. Other colors of beryl are also used as gemstones but are not as well known.

Aquamarine is characterized by a pure sky-blue, bluish-green, or greenish-blue colour, very similar to the tint of sea-water; hence its name, and the old saying that this stone when placed in the sea becomes invisible. Aquamarine of a deep shade of colour is very rare. Aquamarine is colored by trace amounts of iron that find their way into the crystal structure. Most gem aquamarines have been heat treated to produce the popular blue-green colors from less desirable yellow or pale stones. Uncut aquamarines are plentiful but relatively expensive, as would be expected of crystalline gemstone specimens. Aquamarine is, as a rule, very uniformly coloured, irregularities in the distribution or character of the colouring being rare. Crystals are usually transparent to translucent.

Precious beryl, and especially aquamarine, is a mineral of rather wide distribution, occurring in gem-quality at many localities. Aquamarine is abundant in Brazil and the Ural Mountains and elsewhere in Siberia, Russia. It is also found in Colorado and California, USA, Madagascar, Australia, Zimbabwe, South Africa, Norway and Ireland.

The mineral is generally used as a gemstone and as a source of beryllium. It is rather brittle and, therefore, should be treated with care.

Characteristics:

Chemistry: Be₃Al₂(SiO₃)₆, Beryllium Aluminum Silicate   

Class: Silicates

Hardness (Mohs scale): 7.5 - 8.

Density: 2.68 - 2.80 

Refractive Index: 1.57 - 1.59

Dispersion: 0.014

Crystal System: hexagonal;

Crystal Habits: hexagonal prism with pincoid terminations.

Fracture: conchoidal

Cleavage: one direction, poor

Transparency: transparent to translucent

Luster: glassy