Feldspar Photos  
Cochise College               
Photos of Minerals
Geology Home Page

Roger Weller, geology instructor

[email protected]     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 variety of 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)