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Roger Weller, geology instructor regional geology planetary gems
Mr. Roger Weller
One of the most beautiful gems and my favorite is the turquoise
which is an opaque, blue –to -green mineral of hydrous phosphate of copper and
aluminum and the formula for this gem is composed of CuAI6 (PO4)4
(HO)8- 4H2 O.
The term turquoise derives from the “French “ language
“turquois” a dark –blue stone traded and brought to European markets by Venetian
The turquoise is rare, ancient and very valuable of many fine grades and it has been used as ornaments for thousands of years all due to its unique arrays of variable colors. The colors range from white to powder blue to sky blue and even yellowish- green color.
In Bisbee Arizona we have the Bisbee Blue Turquoise from the Lavender Pit, famous all over the world for the deep radiant blue features, and this deep blue is due to the idiochromatic (having characteristic coloration), copper and the green color could be the result of iron impurities or dehydration. The Bisbee Blue turquoise commonly has a hard brown colored matrix.
Bisbee turquoise-photo by Roger Weller
Bisbee turquoise-Photo by Roger Weller
Turquoise Vein from Bisbee Arizona
This is a turquoise vein from Bisbee Arizona, and the term vein in geology refers to a tubular mass of mineral in the fissures, cracks and crevices of an igneous rock. The veins differ greatly in their composition of the material they are intruding. Arizona is one of the main producers of turquoise and the turquoise is mainly a byproduct of copper mining and the Bisbee Blue is by far one of the best turquoises around the world.
Photo is copyright free for non-commercial educational purposes Just credit photo to R.Weller/Cochise college
This is a Turquoise matrix with quartz from Mineral Park in Arizona. Taken by
Green turquoise vein:
Uses of Turquoise:
The turquoise has been used around the world as protection from the powers of darkness, and the Egyptians believed that those who signed a contract wearing a turquoise ring will never know poverty. The ancient used turquoise to inlaid ornaments to decorate their homes and churches. They also believe that it will protect them and their horse from unexpected fall.
Even today in modern history this gem is used as protection for pilots, their crew and those who work in high risk jobs. The Pueblo’s tribe from the Chacon Canyon has the superstition that the turquoise brought them great wealth and many jewelry and artifacts were created by the Southwestern tribes.
Chaco pendant (1000-1040)
The turquoise bracelet comes from Kingman mines which were mined by Leonard
Hardy a shovel operator in the Miami- Globe area in 1949 and he become
interested in making jewelry, marketed and began an operation of selling
The turquoise is considered the Gem of the Southwest. “Bisbee turquoise is as good as it gets. It is a hard turquoise with shades from light to dark blue and a brown to black or sometimes called ‘Smokey’ matrix. Located near Bisbee, Arizona, it is a by-product of a large coppers mine, usually coming from the section known as the ‘Lavender Pit’. The mine no longer produces, thus making Bisbee one of the rarest turquoises. This, plus its quality makes Bisbee one of the most expensive, collectable and sought after turquoise”. (Permission from Nevada Gem.com)
The sleeping beauty comes from the sleeping beauty mine mountain in Globe
Arizona. The turquoise is a favorite of the Zuni Pueblo.
Physical characteristics of turquoise:
One of the Turquoise properties is the hardness which ranges from 5 to 6 on the Mohs scale.
As a Hydrated Copper Aluminum Phosphate mineral, turquoise is composed of aluminum, copper, phosphorus, hydrogen and oxygen. Turquoise is an example of a typical phosphate as it is often strongly colored and average in hardness (www.theimage.com and www.mineral.galleries.com)
Luster: Dull to Waxy
Transparency: semi-transparent to opaque
Crystal Habits: Crystals rarely visible without microscope
Fracture: Conchoidal and smooth
Cleavage: Perfect in 2 directions, rarely seen.
Specific Gravity: 2.6-2.9
Chemistry: CuA16 (P0 4)4(OH) 8 4H20
Associate minerals are: pyrite, limonite, quartz, and clay.
Other Characteristics: color can change with exposure to skin oils.
Formation of Turquoise:
Turquoise is formed from the pre- existing minerals as secondary mineral during the percolating acidic aqueous solution that happens by weathering and oxidation and is an Opaque, cryptocrystalline mineral, composed chiefly of hydrated aluminum phosphate, Al2(OH)3PO4· H2O.
Mostly turquoise is found in climates that very dried.
Notable Occurrences: include Arizona and New Mexico, USA; Australia; Iran;
Afghanistan and other localities in the Middle East.
Works cited for this report are as follow:
Dulyan, Aram. www.wikipedia.org/wiki/turquoise Oct 9th 2008.
Oct 9th 2008.
Perkins. p472, http:/webminerals.com
Oct 8th 2008.
Weller, Roger. Roger Weller, geology instructor. Cochise College
October 9th 2008.