Stone of the Week - Amazonite (Amazonstone)

Amazonite or Amazonstone, belongs to the major mineral group of Feldspars, and the subgroup called Microcline. Feldspars are a group of minerals composed of aluminum silicates, and are the most common rock forming minerals on Earth. Amazonite derives its name from the Amazon River located in South America (even though it has not been found along the river).

Amazonite usually refers to the pale blue to richer blue colors of Amazonite.


Amazonite is commonly further divided as two varieties. Amazonite or Amazonstone is often the pale blue-green colored stone, sometimes a light sky to slightly richer blue color. Russian Amazonite is the variety that has a very rich blue-green color with streaks of white. It has a rather limited occurrence, and is primarily collected in Russia and Colorado (US). It is believed that Amazonite gets its blue-green color from the inclusion of water and lead within its molecular structure.


Russian Amazonite often refers to the richer green/blue-green variety with white striations.


Amazonite has been used throughout history for ornamental decoration for its lovely blue-green colors as well as its play of color (schiller). Amazonite was used by ancient Egyptians in numerous carvings; they possibly considered it a medium between the humans and gods. Some use it for metaphysical purposes, as it is thought to have a calming effect. Today it is commonly used for lapidary/jewelry purposes, though care must be taken as it can fracture easily. A popular form is a combination of Amazonite with other minerals such as Pyrite, black Tourmaline, and varieties of Quartz.

Amazonite makes for a lovely color to add to jewelry. As pictured in the pendant on the left, it is also sold with a combination of minerals including Pyrite, Tourmaline, and/or Quartz.



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Amazonite Facts:
Chemical composition: K[AlSi3O8]
Crystal System: Triclinic
Color: Blue-green
Habit: Prismatic, Tabular
Fracture: Irregular/Uneven, Conchoidal
Cleavage: Perfect
Luster: Vitreous
Transparency: Opaque to translucent
Hardness: 6-6.5
Specific Gravity: ~2.55
Streak: White
Occurrence: Worldwide, but most commonly in the US, Madagascar, and Russia



References
A Guide to Rocks and Fossils by B. Busbey III, R. R. Coenraads, P. Willis, and D. Roots. Published 2002 by Fog City Press. ISBN: 1877019518

Rocks, Minerals, & Fossils of the World by C. Pellant and R. Phillips. Published 1990 by Little, Brown and Co. ISBN: 0316697966

Mindat – Microcline. http://www.mindat.org/min-2704.html

Wikipedia – Amazonite. http://en.wikipedia.org/wiki/Amazonite