Peridot

(Part 2)

Arizona.--Currently, the United States is the basic supplier of peridot to the world gemstone industry. Deposits in Arizona are the major source of U.S. peridot. Faceted Arizona peridot is highly prized locally, but also enjoys widespread popularity for the manufacture of birthstone and other jewelry. The bright green, yellow-green to olive-green peridot is used both as a faceted and tumbled gem. The faceted stones are used in rings, earrings, pendants, bracelets, and as accent stones. The tumbled gems can be set in baroque jewelry, drilled and strung as beads, used in mosaics, and in the manufacture of gem trees.

Peridot Mesa, located on the San Carlos Apache Indian Reservation east of Globe in Gila County, is the most productive locality for peridot in the world. A second Arizona location from which peridot is recovered is Buell Park Apache County, Arizona, about 16 kilometers north of Fort Defiance. However, it is estimated that 80% to 95% of the world's production of peridot comes from the San Carlos Reservation.

The peridot occurs as individual grains and aggregates of grains in a basalt which is about 3 to 35 meters thick that forms the top and sides of Peridot Mesa. The material is recovered after it has weathered out of the basalt, in the gullies and canyons which lead down the sides of the Mesa or it is recovered in place in the basalt. The latter method of recovery requires drilling and blasting. The peridot grains that are commercially recovered are typically 6 to 13 millimeters in size. Therefore, the faceted stones produced from this material are generally about 1 carat in size; 2 to 3 carat stones are not uncommon, but stones, particularly flawless ones, 5 carats and over are unusual. Stones as large as 15 and 22 carats have been cut from San Carlos peridot...

to be continued...