Feldspar Photos  
Cochise College               
Photos of Minerals
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Roger Weller, geology instructor

wellerr@cochise.edu     copyright 2008-R.Weller

 
feldspar-variety sunstone from Oregon
Oregon sunstone is the official state gemstone of Oregon.
Color range: colorless, pale yellow, soft pink, blood red, deep blue, and green.
Color is caused by microscopic blebs of copper.
This feldspar is labradorite.  
 

feldspar
Photo is copyright free for non-commercial educational uses.
Just credit photo to R.Weller/Cochise College.
 

These labradorite phenocrysts occur in the decomposing Steens Mountain Miocene lava flow.
The outcrop is 10 km north of Rabbit Hills in Lake County, Oregon and covers 3 km². 
The copper content ranges from 0 to 300 ppm.
The labradorite crystals range in size up to 8 centimeters.

references:

American Mineralogist, v.51, (1966), p. 177-178: Physical properties of calcic labradorite from
Lake County, Oregon (D.B. Stewart and others).

Geology, v.13 (1985), p.644-647: Exsolution of metallic copper from Lake County labradorite
(A.M. Hofmeister and G.R. Rossman).
 

The Ore Bin, v.34, no. 12 (Dec. 1972), p.107-215: Oregon "sunstone" (N.V. Peterson).

Oregon Geology, v.49, no.2 (Feb. 1987), p.23-24: Oregon sunstones (R.P. Geitgey)