Aquamarine gemstone beads & coloration

Aquamarine is an affordable gemstone belonging to the Beryl family (chemical formula Be₃Al₂(SiO₃)₆). Pure Beryl is colorless.  However, some impurities cause the diverse amount of colors and many varieties. The pale blue color of aquamarine is attributed to iron impurities’ ions Fe²⁺.  The Fe³⁺ ions produce golden-yellow color, and when both Fe²⁺and Fe³⁺ are present, the color is a darker blue due to Fe²⁺-O-Fe³⁺ inter-valence charge transfer.  Aquamarine ranges in color from a faint light blue to blue and bluish-green, due to the concentration of iron impurities and its ions valence state, with lighter colored stones being the more common type.

The green hues in most Aquamarine can be removed through heat treatment. Its color fades to white when exposed to sunlight or is subjected to heat treatment. Natural Aquamarine is usually lighter and greener in color, and heat treatment creates deeper bluer hues due to change of iron impurities’ ions valence state.

Aquamarine has good hardness (7.5 to 8 on the Mohs scale), the hardness makes it very tough and protects it to a large extent from scratches, but it may develop internal cracks if banged hard.  Aquamarine is belonging to hexagonal crystal group, its moderate refraction and its weight in common with the other members of Beryl family.

Aquamarine gemstone is mined mainly in Brazil, but also is found in Nigeria, Madagascar, Zambia, Pakistan, and Mozambique. In the United States, aquamarines can be found at the summit of Mt. Antero in the Sawatch Range in central Colorado. In Wyoming, aquamarine has been discovered in the Big Horn Mountains.

The largest aquamarine of gemstone quality ever mined was found in Marambaia, Minas Gerais, Brazil, in 1910. It weighed over 110 kg, and its dimensions were 48.5 cm x 42 cm.

High quality flawless single crystal aquamarine is cut to form gemstone beads to maximize the intensity of its color, and to display cat's eye effect and asterism.  Lesser quality poly-crystal aquamarines lacking good transparency are formed into stone beads with different shapes.