Oregon Sunstone

Oregon Sunstone is a gem variety of plagioclase feldspar (in the labradorite composition range) found in the U.S. state of Oregon, where it is the official state gemstone. Unlike most sunstones, its color and sparkle come from elemental copper.

Microscopic copper platelets produce the glittery aventurescence (called schiller), while dissolved copper imparts natural body colors ranging from clear and pale yellow to pink, salmon, deep red, and green, including prized bicolor stones. This natural copper coloration is unusual and makes fine Oregon Sunstone highly valued.

It is mined from basalt lava flows and is appreciated for being a naturally colored, untreated gemstone in a market where many feldspars are enhanced.

Oregon Sunstone formed as plagioclase feldspar phenocrysts crystallizing within copper-bearing basaltic lava flows. As the magma cooled, copper was incorporated into the growing crystals; slow cooling allowed some copper to exsolve into tiny oriented platelets that create the shimmering schiller, while copper remaining in solution produced the red, green, and bicolor body tints.

The gems are recovered from weathered basalt and surrounding soils in high-desert areas of central and southeastern Oregon, including well-known deposits in the Ponderosa and Rabbit Basin (Plush) areas. Crystals are typically dug from decomposed lava or mined from harder host basalt, then cut to display color and schiller.

Oregon Sunstone is a plagioclase feldspar of Mohs 6.5-7 with two cleavages near 90 degrees and a vitreous luster. Diagnostic features are its natural color range (clear, yellow, pink, red, green, bicolor) and the metallic copper schiller of glittery internal platelets.

The copper aventurescence appears as directional metallic flashes within the stone, distinct from surface glitter. Color zoning and bicolor red-green stones are characteristic and prized.

Distinguish it from Indian/other sunstones (which sparkle from hematite, giving a more orange-brown glitter) and from glass goldstone imitations (which have dense, uniform copper flecks and no cleavage). Natural Oregon material is untreated, unlike copper-diffused andesine.

Oregon Sunstone is used almost entirely as a gemstone. It is faceted to showcase its natural red, green, and bicolor hues, or cut as cabochons to display the copper schiller, and is set in rings, pendants, and earrings. Stones with strong saturated color, especially red and green or bicolor, and bright schiller command the highest prices.

Its appeal is enhanced by being a naturally colored, untreated gem and the official Oregon state gemstone, which supports a notable local mining and lapidary industry.

Metaphysically, sunstone is associated with vitality, warmth, leadership, and optimism, though these are traditional beliefs rather than proven properties. Its good hardness makes it well suited to most jewelry.