TRUGEMS

TRUGEMS Table of Contents Page

Sunstone Markets

Golden Sunstone

Virtual Star

Virtual Cross

VR Stone Prices

NATURAL SELECTION

 

GOLDEN SUNSTONE

 What is golden sunstone?

      Golden Sunstone is labradorite - a member of the plagioclase group, within a family of minerals known as feldspars. Feldspars are present in many of the exposed rocks of our planet. They are perhaps the most abundant minerals in the earth’s crust and tend to be pale colored and opaque. Transparent feldspars are extremely rare and are typically colorless. It is therefore very unusual to find labradorite in brightly colored transparent crystals. Golden sunstone is unique on earth in terms of its amazing clarity, uniform saturated color, large average size and the polish attainable on faceted surfaces.

Where does sunstone come from?

   SSunstone is a product of dark-colored volcanic rocks, such as basalt. While basalt covers thousands of square miles of the earth’s surface, only in a few scattered localities does the rock contain large, distinct crystals of labradorite. The best known such locality is the area near the city of Plush in western Oregon, where sunstone occurs in a wide range of colors including pale yellow, beige, pink, green, orange and red. Sunstone is the official state gemstone and accounts for the majority of the value of Oregon’s gemstone production. The colors in Oregon sunstone are caused by the presence of copper, which often appears as metallic inclusions that reflect light and create an effect called “Schiller”. Oregon sunstone is typically “cloudy” and translucent, rather than transparent, and the yellow shades are extremely pale. Small cut gemstones generally look “washed out” and the yellow shades are actually almost colorless. Oregon sunstones in yellow, pink and coppery colors generally range in size from about one to five carats; green and orange stones tend to be smaller and are rare above five carats. The largest Oregon sunstone recorded (known as “the Promise”) weighs about 54 carats and displays the “Schiller” effect so typical for this locality.

What makes golden sunstone unique and different?

   Golden sunstone comes from a deposit unlike any other in the world. The feldspar in this unique basaltic lava flow displays none of the pink, orange and green shades typical of Oregon material. Rather, the sunstone here is totally uniform in hue – a rich, golden straw yellow that appears to deepen in large faceted gemstones. The crystals do not contain copper and are almost always completely transparent. The average size of crystals from this locality would yield cut gems between 3 and 10 carats, with stones over 20 carats available on a regular basis. Transparent faceted gemstones over 100 carats have already been cut, making golden sunstone by far the largest known cuttable plagioclase feldspar in the world.

    The hardness of golden sunstone is slightly greater than that of other feldspars, and the material can be polished with the very high degree of reflectivity normally seen only in extremely hard gemstones such as diamond, chrysoberyl and sapphire. This unique reflectivity, combined with the relatively low refraction typical of feldspar, creates a new phenomenon not observed in other gemstones. Named “pseudo-dispersion” by noted author and gemologist Dr. Joel E. Arem, this phenomenon results from the “capture” and reflection, by a gemstone’s facets, of colors in the surrounding environment. These colors are transmitted to the observer’s eye and appear to be generated by and within the cut stone, thus resembling the phenomenon of “dispersion” seen in gems such as diamond. In fact, many jewelers have remarked that golden sunstone looks like yellow diamond!

 Is golden sunstone expensive?

    Despite its great rarity and beauty, golden sunstone is surprisingly affordable. Cut gems are available in all the shapes common to manufactured jewelry and in sizes ranging from under one carat to more than 10 carats. Prices for these stones are in the range of several tens of dollars per carat, rather than hundreds or thousands! Unique, larger stones are individually priced.

 © Joel E. Arem 2000, 2002

 

 

 

Send mail to webmaster@trugems.com with questions or comments about this web site.    Copyright © 2005 TRUGEMS, Inc.      Last modified: May 06, 2005