The jadeite mines of Upper Burma (now Myanmar) occupy a privileged place in the world of gems, as they are the principal source of top-grade material.

General Electric has developed a variety of high-temperature annealing techniques at different pressures for enhancing the optical properties of polycrystalline synthetic diamond films and single-crystal synthetic diamond.

Gemological, chemical, spectroscopic, and microscopic properties of blue-green color-change garnets from a new deposit near Bekily, Madagascar, are given.

Gem-quality synthetic ametrine has been produced commercially in Russia since 1994.

Criteria for distinguishing emerald filling substances were investigated.

Greater amounts of colorless sapphire—promoted primarily as diamond substitutes, but also as natural gemstones—have been seen in the gem market during the past decade.

Over the last 10 years, millions of carats of turquoise have been enhanced by a proprietary process called the Zachery treatment.

More than 400 blue diamonds were studied at the GIA Gem Trade Laboratory over several years to reveal additional information about the relationships between their color, clarity, and other gemological properties.

A mathematical model which can analyze how appearance factors depend on proportions.

The successful culturing of abalone pearls has been known since French scientist Louis Boutan’s experimentation in the late 1890s, but commercial production has been achieved only in recent decades.

Two ecclesiastical objects of the late Gothic period (1350–1520) were investigated to identify the gemstones that adorn them.

Natural and synthetic gem rubies can be separated on the basis of their trace-element chemistry.

This article reviews the rise of the modern diamond cutting industry in India and its impact on the world diamond trade.

Synthetic emeralds grown hydrothermally in an alkali-free, chlorine-bearing solution have been manufactured in Guilin, China, since 1987.

Some gem diamonds fluoresce, most commonly blue, to the concentrated long-wave ultraviolet radiation of a UV lamp.

Commercial quantities of gem-quality benitoite are known from a single location in the world, the Benitoite Gem mine in the New Idria district of San Benito County, California.

An investigation of the difference between synthetic opal and opal simulant.

New mining techniques have combined state-of-the-art equipment and technology to detect and extract large, fine-quality rhodochrosite specimens and gem rough.

Examination of 51 colorless to near-colorless synthetic diamonds from all known sources of production confirms that they can be distinguished from similar-appearing natural diamonds on the basis of their gemological properties.

Ruby crystals from Southeast Asia with a fixed six-rayed star, similar in effect to trapiche emeralds from Colombia, are described.