GIA ensures accurate gemological measurements across its global laboratories through rigorous metrology practices, including systematic instrument calibration, validation from traceable standards, and ...

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.

View the holiday schedule for all GIA locations worldwide.

Field Report Gems & Gemology, Fall 2013, Vol. 49, No. 3 Three Occurrences of Oregon Sunstone Duncan Pay, Robert Weldon, Shane McClure, and Kevin Schumacher ...

Blue diffusion-treated sapphires are becoming more prevalent than ever before. The diffusion technique, which involves the addition of color-causing chemicals during heat treatment, results in a thin ...

Several diamonds were treated for the purposes of observation and report with a new laser technique which does not show the typical surface-reaching drill hole.

The northeastern portion of the state of Minas Gerais, Brazil, contains the world's greatest concentration of complex granitic pegmatites, which are especially noted for the production of gem beryl, ...

Field Report Gems & Gemology, Winter 2016, Vol. 52, No. 4 Update on Gemstone Mining in Northern Mozambique Wim Vertriest and Vincent Pardieu ...

Since late 2007, rubies and sapphires have been mined by hand methods from both eluvial and primary deposits at Winza in central Tanzania.

Gem-quality brownish red zircon occurs in alluvium derived from Tertiary alkali basalt at Muling in the northeast Chinese province of Heilongjiang. Rough and cut samples were characterized using ...

Analyzes the effects of coating on green jadeite specimens using DiamondView imaging, microscopy, spectroscopy, and Raman spectrophotometry.

Observing a water drop’s interaction with opal, as well as refractive index, can confirm a specimen’s hydrophane nature with less risk of breakage than total immersion.