Chameleon diamonds are among the rarest of gem diamonds.

Using a multi-step process, Lucent Diamonds has developed a new treatment process for certain natural diamonds that creates colors from pink-purple through red to orangy brown.

A new chart, supplementing the one published in the Winter 1995 issue of Gems & Gemology, summarizes the features of both as-grown (“non-modified”) and treated (“modified”) synthetic diamonds currently in the gem market (that is, those grown by the high pressure/high temperature technique).

Peridot: The ultimate value of a gemstone suite lies not only in the cost and quality of the materials themselves, but also in the selection of the rough, the quality of the faceting, and the intricacy of the setting in a well-designed and well-manufactured suite of jewelry.

For more than a century, the Four Peaks mine in Maricopa County, Arizona, has produced gem-quality amethyst from crystal-lined or crystal-filled cavities and fractures in a brecciated quartzite host rock.

The GIA diamond cut grading system described here includes the components of brightness, fire, scintillation, polish, and symmetry, as well as weight and durability concerns, into a single overall grade for cut quality for standard round brilliants.

This article compares some of Chatham Created Gems’ synthetic colored diamonds to natural diamonds and explains the results.

In recent years, the obligation to fully disclose all gem treatments has changed from a mere ethical responsibility to a legal one.

A compilation of gem news from around the world, covering topics such as localities, unusual gem materials, market news, new products, discoveries, jewelry manufacturing techniques, and industry trends.

This article provides an overview of the history of natural and cultured pearls from Mexico, describes pearl culturing at the Guaymas farm, and focuses on the properties of bead-nucleated cultured pearls from P. sterna.

This article presents information about the CVD process, the history of its development, and properties that differentiate the resulting synthetic crystals from natural diamond.

There is only one known commercial occurrence of gem-quality red beryl in the world: the Ruby Violet (or Red Beryl) mine in the Wah Wah Mountains of Beaver County, Utah.

Pezzottaite, ideally Cs(Be2Li)Al2Si6O18, is a new gem mineral that is the Cs,Li–rich member of the beryl group.

Brown-to-gray and near-colorless single-crystal type IIa synthetic diamonds grown using a chemical vapor deposition (CVD) technique by Apollo Diamond Inc. have gemological properties that are distinct from those of both natural diamonds and HPHT-grown synthetic gem diamonds.

Black and dark gray diamonds from Siberia, Russia, were studied by analytical scanning and transmission electron microscopy.

The stories behind seven strikingly beautiful rare natural diamonds, united in an exhibit at the Smithsonian, are told here.

The heat treatment of corundum involving lattice diffusion of beryllium (Be) at temperatures over 1800°C has become a major issue in the gem trade.

Gemological, chemical, and spectroscopic properties are presented for the first known transparent faceted grandidierite.

Just because you don’t see it, doesn’t mean it isn’t there. Many areas in the jewelry industry—education, gemological research, lecturing, publication, and laboratory and inventory documentation, to name a few—either require or benefit from high-quality photomicrography.

The rare borosilicate poudretteite, a mineral that previously had been identified only as tiny crystals.