Sunstone: A little known, but beautiful Gem

Sunstone is a variety of Labradorite feldspar that generally shows an opaque "schiller" effect where the metallic inclusions reflect light in a blaze of color. However, it can also come in clear stones which are suitable for faceting. These facetable forms are usually pale yellow, but in Oregon they are also found in beautiful shades of Red, orange and green. Sunstone is a gemstone that is formed as crystals in slow cooling basaltic lava flows, much like Peridot. Sunstone is actually closely related to moonstone. Sunstone is the State Gem of Oregon, which is the prime source for this beautiful Gem. Large quantities of gem-quality labradorite, most of it water-clear, straw yellow, or yellow sunstone, have been produced from deposits in southeastern Oregon for many years. In the shiller type of  sunstone, the labradorite contains millions of copper colored platelets that reflects the light with varying intensities resulting in a golden-red play of color. The "Schiller" phenomenon makes the stone appear to "glow" as if it had it's own internal light source.  Sunstones with Schiller retain this unique "glow" even when viewed from a great distance and by evening lights. In fact, the presence of these bright inclusions was the reason for naming it Sunstone or Heliolite, from the Greek helios for sun and lithos for stone. Although the common color of Oregon sunstone is straw-yellow, it also can be pink, peach, red, salmon red-orange, red-green, and blue-green. It also can be bicolored and tricolored in combinations of yellow, red, and green, and a small percentage is di- and tri-chroic. Oregon Red Sunstone differs from Sunstones found in other worldwide locales in color, a strong pleochroism, showing multiple colors in a single stone. Unlike many gemstones on the market, sunstone is not treated or altered to improve its appearance. Some geologists who have studied the Oregon sunstone believe the color is caused by the element copper.

Oregon Red Sunstone is an unusual American Gem distinguished from other Feldspars by its unique chemical and physical properties. It is a bright Gem, with or without the Schiller effect, that creates outstanding jewelry. Depth of color and degree of clarity determines the carat price. Those Sunstones which are the Reddest and have fewer inclusions command the highest Carat price.
 

SOURCES OF SUNSTONE

The most famous source of fine sunstones is the state of Oregon in the US. A number of old basalt flows within this state contain the valuable red gem. The best known is located near the tiny town of Plush, in the south central part of the state, not far north of the Nevada border. These deposits are being actively worked by a couple of different companies.  Sunstones are mined from the surface from partially decomposed rock with a pick and shovel, or mechanically with bull dozers and other equipment. Shallow pits are dug to retrieve the rough material which is mixed in with basalt rock. It has to be screened and the gem crystals separated from the rock by sight. Un-weathered deposits release rough only by blasting and tunneling which often shatters the Sunstone rough. Because of cold weather and the remote location, the mining season averages approximately six months.

There is actually sunstone area which has been set aside for the public to work. In the gem area near Plush, the BLM has set aside 4 square miles for rock collectors to hunt for sunstones. No claims can be filed within the BLM sunstone area, and there is no charge to prospect. Even though thousands of rockhounds have visited this deposit, there are still stones to be found. The area also produces a valuable adventurecent cabochon material with a bright copper sheen. Other sunstone mines in the Plush area are also open to the public for a fee.  Click here to see Chris' page on visiting the SUNSTONE MINES AT PLUSH, OREGON

 In 1980, the availability and quality of sunstone, other than the standard yellow Oregon variety, drastically increased with the discovery of another sunstone deposit that was to become the Ponderosa Mine near Burns. The vivid-red faceted stones and velvety-red cabochons from this mine set a new world standard for beauty, not just for red sunstone, but for any sun-stone. The opening of the mine also increased the supply of peach, salmon red-orange, red-green, green, blue-green, and bicolored and tricolored in combinations of yellow, red, and green. It seems that because of these multiple sources, that for the first time ever, there was a continuous U.S. supply of the more desirable colors in most of the calibrated sizes up to several carats needed by the jewelry industry.  The supply from the Oregon deposits should continue to be adequate for many years into the future.

Some other sunstone gems are also found in India and Tanzania. The Indian sunstone shows a coarser sparkle in the shiller that is present in the stones when compared to the Oregon stones. It is said that the source of the shiller in the Indian stones are included crystals of Hematite.

CHOOSING A SUNSTONE

The transparent Oregon Sunstone feldspar gems from this area that are suitable for faceting come in a variety of colors, including pale yellow, salmon pink, green and the highly desirable bright red hue. Clean Red Sunstone is much rarer and commands true Gemstone prices! It is a rare and sought after collector's item and makes for spectacular jewelry. There is only a limited production of the finest quality red Sunstone from the operating mines in Oregon. The red facetable feldspar found at the Plush deposit is a distinctly American gem, being found only in Oregon. In addition, the quality of the copper colored sunstone material from Oregon is better than anywhere else in the world. The Oregon Sunstone is now becoming much more widely accepted as a Gem, and the prices are tending to move upward.

The most important factor in the value of a transparent sunstone is its color. The finest stones possess deep red tones with no contained shiller or other inclusions to dull or reduce the sparkle. Larger deep red stones are uncommon and may command a significant price. In fact the largest known clean, faceted high-quality red sunstone is only a little over over 10 carats. Cabochons of fine shiller stones are also highly valued, though they are priced less than the transparent red stones. The shiller stones are also available in larger sizes.