Picture Jasper

Jasper occurs worldwide, and picture jaspers are usually named after their localities. Oregon's Biggs Jasper is now the most common source; it is a jasperized volcanic ash from Biggs Junction, Sherman County, Oregon. Bruneau Jasper from Bruneau Canyon, Idaho, was once the preferred material, but a dam has submerged the mining site and it is now quite rare.

Picture jasper is recognized by its opaque, dense body and scene-like pattern; the name describes a pattern, not a separate mineral. Jasper is commonly dyed (detected by appearance, spectrum or Chelsea filter) and is sometimes heated to change its color, which is undetectable. Glass and porcelain-like baked clay can imitate jasper; glass has a vitreous luster and lower hardness.

According to the International Gem Society, all types of jasper take an excellent polish, are trouble-free to care for and are hardy enough for all jewelry uses.

Picture jasper is among the materials displayed in the Janet Annenberg Hooker Hall of Geology, Gems and Minerals of the Smithsonian's National Museum of Natural History in Washington, D.C. Jasper in general has been used in jewelry since the early history of civilization.