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A round, bright red gem displayed on a dark gray background.
Article
The Red Hot Gems of Summer

These red, pink and orange hued gems evoke passion and excitement – and are sure-fire accessories for sultry summer days.

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John Woodmark, CEO of the Ponderosa mine, is a man in his element. - Robert Weldon
Article
A Sunstone Odyssey, Part 1: The Ponderosa

The first of a three-part series exploring Oregon’s state gem reports on a July 2013 visit to the Ponderosa mine, a prolific sunstone source surrounded by majestic ponderosas.

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Sunstone Labradorite from the Ponderosa Mine, Oregon

The Ponderosa mine is now producing commercial quantities of the gem-quality labradorite feldspar known as sunstone.

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The Chinese red feldspar controversy: chronology of research up until July 2009

Red copper-containing plagioclase feldspar from Oregon has been available for over a century. In the early 2000s, new localities for copper-bearing feldspar were reported from the Democratic Republic of the Congo and from Tibet or an unspecified locality in China.

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A graceful carving displays this Oregon sunstone’s bright, reflective copper inclusions, its intense colour and its pleochroism. – Robert Weldon, courtesy Oregon Sunstone
Article
Sunstone Description

Not all feldspars that bear the name “sunstone” are from the same side of the feldspar family - both the orthoclase and the plagioclase species boast a sunstone feldspar variety. The name sunstone refers to the gem’s appearance rather than to its chemical makeup.

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Dr E. J. Gübelin Collection Danburite
Article
GIA's Gübelin Gem Project: Various Gems, Danburite – Humite

Among the collection assembled by Dr Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

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