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The Plush, Oregon, Sunstone gem field (Near Hart Mountain) is located approximately 50 miles northeast of Lakeview, Oregon, and 20 miles north of the tiny town of Plush. You wont see any redwood trees in the area, but there are plenty of jackrabbits!
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The arid south-central portion of Oregon is a classic volcanic region. There the relatively young rock consists of dark basalts, andesites, rhyolites, ash and cinders. |
Millions of years ago a magma chamber several miles below the surface supported the correct geochemical conditions for the growth of labradorite, a calcium-rich plagioclase feldspar. These crystals grew as phenocrysts in the basalt magma and eventually reached the surface through magma outflows. Also present in the magma was a small amount of copper that co-crystallized with the labradorite. It is the trace amounts of copper, forming tiny platelets, that gives rise to the unusual aventurescence or "schiller" of much of this Sunstone. |
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The Sunstone gem fields have long been a favorite with collectors. Portions of the gem field have been reserved for collecting by the general public; other areas have been commercially mined on a small scale for many years. Other sunstone deposits occur in the same general area of the state and produce equally beautiful gems. |
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(See "Mining the Sun" by Chris Johnston, Lapidary J., Vol. 44, No11, pg. 75, 1991 or Gems & Gemology, Winter, 1991). |
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