Amethyst may develop into the more common citrine and rarer green quartz naturally under certain geologic conditions. On the California-Nevada border, just north of Reno, amethyst, citrine, and green ...

Although lost for literally hundreds of years after the Spanish conquest of the Aztecs, many deposits of jadeite have been found in Guatemala during the last two decades. Following the discovery of ...

Jewelry-quality synthetic malachite is now being manufactured in the USSR. The texture, structure, and physical and physico-chemical properties of this synthetic malachite are reported. Three textural ...

Figure 1. Bicolored elbaite tourmalines (5–8 ct) from the Himalaya mine in Southern California are set with yellow diamonds, tsavorites, and red-purple elbaites. These custom-made earrings, ring, and ...

Although cultured pearls dominate the freshwater pearl industry, the rarer natural freshwater pearls are still encountered during routine laboratory testing. The majority of these have been handed ...

Blue sapphires are currently being mined on an exploratory basis from alluvial deposits at the Lindi mine, near the town of Mingxi in Fujian Province. The geology and occurrence of the sapphires ...

ペリドット、スピネル、サードニックスが8月の3つの誕生石です。ペリドットの誕生石は、苛酷な条件の下で形成されることで知られています。地球のマントルの奥深くから溶岩とともに ...

An emerald deposit at Byrud, in southern Norway, yielded significant quantities of crystals and gem rough in the late 19th and early 20th centuries. Complex multiphase inclusions in the emeralds ...

This course examines jewelry’s important features and how they combine to give a piece its unique value. Content includes the unique qualities of precious metals, how to describe them to customers, ...

GIA Student Workrooms give you affordable access to all the equipment and gemstones you need to complete the practical requirements of your Gem Identification course through Online Education. This ...

Figure 1. The largest known natural moissanite crystal, found along the Kishon River in northeastern Israel, measures 4.1 mm in its longest dimension. Photo by Vered Toledo. Synthetic silicon carbide ...