Sunstone

Sources include Oregon in the United States and Tamil Nadu in India. In Oregon, sunstone is found in ancient lava fields of the Warner Valley high-desert area in the south-central part of the state, where many varieties are unique to the region; Oregon sunstone is a transparent feldspar with copper inclusions. Finds in Norway and Siberia in the 19th century made sunstone more widely available.

Reflective inclusions can produce glitter, but not every sunstone sparkles. Goldstone is a copper-bearing glass imitation, not a sunstone alias.

The glitter is called aventurescence: a sparkly, metallic-looking luster from flat, reflective inclusions; when it is present, gemologists call the material aventurine feldspar. Small inclusions give a reddish or golden sheen, larger ones give glittering reflections. The inclusions may be hematite, copper or another mineral: Indian aventurine feldspar has a red-brown body color, while Oregon sunstone (a labradorite) contains copper and its color is natural, not the result of treatment. Material sold in the 2000s as "Tibetan sunstone" or "Tibetan andesine" was found by several laboratories likely to be pale andesine treated by copper diffusion.

Clean with warm, soapy water. Avoid impacts, heat, steam and ultrasonic cleaners. Sunstone has poor toughness because of two cleavage directions, so protective settings such as pendants, earrings and pins suit it better than rings. Its color is stable to light. Feldspars are rapidly attacked by hydrochloric acid, so avoid cleaning products containing bleach; rare fracture-filled stones should only be cleaned with warm, soapy water.

In the early 1800s sunstone was a little-known, rare and costly gem; finds in Norway, Siberia and elsewhere later made it more widely recognized and less expensive. In Oregon, sunstone finds in the Warner Valley were reported in the early 1900s, and Native Americans in that area may have been the first collectors of these stones; a museum in Jacksonville, Oregon, displays sunstones among its Native American artifacts. The 1987 Oregon Legislature designated Oregon sunstone as the state gemstone.

Oregon sunstone is the official state gemstone of Oregon, designated by the state legislature in 1987.

According to a Native American legend recounted by GIA, the blood of a great warrior wounded by an arrow dropped onto pieces of Oregon sunstone; the legend says his blood carried his warrior spirit into the stones, coloring them red and giving them sacred power. This is a legend, not an established property.