The specimen displayed is a variety of microcline feldspar, referred to as amazonite. Many jewellers love this mineral for making cabochons because of its brilliant colour, which is thought to be caused by traces of lead and water. The gemstone is called the “Stone of Hope”, because it is thought to inspire confidence and hope. The name “amazonite” comes from the Amazon River in South America. It can also be found at the Lake George area, along with smoky quartz. However, its occurrence is very limited.
This specimen of amazonite was mined in the Lake George area of Colorado. ASW Veatch specimen (photo Steven Marquez).
Facts on file
Chemical formula: KAlSi3O8
Composition: potassium aluminium silicate
Colour: bluish green or verdigris green
Crystals: triclinic
Cleavage: good, two directions at 90o
Fracture: uneven
Lustre: vitreous
Streak: white
Hardness: 6
Transparency: none
Specific gravity: 2.56-2.57
An amazonite haiku:
Microcline feldspar.
Bluish or verdigris green.
The perfect jewellery
Chesterman, Charles W. The Audubon Society Field Guide to North American Rocks and Minerals. New York: Alfred A. Knopf, 1990.
Hall, Cathy. Smithsonian Handbooks: Gemstones. New York . Dorling-Kindersley, 2002.
Steven Marquez (USA)
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