Prior to the finds of substantial amounts of facetable plagioclase feldspar crystals in Oregon, most sunstone, much of which came from India, was opaque and used for cabbing, bead, or carving material. Such is the case no longer. An incredible variety of high value sunstone rough is now being extracted by several mining companies as well as on public collecting sites in Oregon. Although most of the rough is pale yellow in color, a substantial amount of more interesting material is being found. Two main features are notable in high value rough collected from this location: 1) strong body colors ranging from pinks and tans to oranges, greens and reds as well as bi- and tri-colors, and 2) fine grained coppery shiller which allows for transparency in the stone yet still produces the phenomenon of aventurescence or "glitter". Every combination of shiller or lack of it, and color is found.

Collectors and jewelry lovers from all over the world are fast becoming aware of this uniquely American gemstone and appreciate it as one of the shrinking number of materials that can be correctly assumed to be completely untreated and unenhanced.

As with other feldspar gems, gentle treatment and protective settings are called for, and use in everyday rings is not advisable. To date there are no synthetics in the market.

Value

Because there are so many different kinds of sunstone, the values range widely. The least valuable form is the pale yellow to colorless non-shiller type which in commerical cut, or calibrated stones may go for a few dollars per carat, and for custom cut stones somewhat more. The pinks and tans with and without shiller have additional value, depending on the color and effect. Some greens, strong pinks and reds as well as the bicolored and tricolored stones with and without shiller are much more valuable. The most desirable color is red with large (over 3 carat) stones of prime color retailing at prices rivaling fine sapphires and emeralds. The best greens are very rare and can cost more than the best reds. Oregon sunstone, especially shiller or bi-color pieces are often used for fine art carving material; and the carvings are valued as much for their artistic merit (and the fame of the artist) as for the value of the material itself.

Gemological Data

Makeup: a calcium rich species of plagioclase feldspar,

sometimes with copper or hematite inclusions and traces of iron; 32% Albite, 68% Anorthite

Luster: Vitreous

Hardness: 6 - 6.5

Cleavage: 2, Perfect

Fracture: splintery to uneven

Density: 2.70

RI: 1.56 - 1.57