The 75.47-carat Hooker Emerald was worn by Ottoman Sultan Abdul Hamid II, the last sultan of the Ottoman Empire. Photo by Chip Clark, courtesy Smithsonian Institution, National Museum of Natural ...
Ruby is the July birthstone – and it’s one of the most coveted of gems. The name is derived from the Latin word ruber, meaning “red” – the color of love and passion. Few things catch the eye like the ...
Pietersite has been described as a brecciated variety of tiger’s-eye. This study examined pietersite specimens from Namibia and China (the main sources) using powder X-ray diffraction, optical ...
Emeralds are formed when chromium, vanadium, and iron are present in the mineral beryl. The varying presence of these three elements gives emerald its range of color. Chromium and vanadium make an ...
Visit us at the 70 th Bangkok Gems & Jewelry Fair to learn what’s new at GIA and take advantage of quick, convenient gem identification and origin identification services for colored stones at our ...
The approximately 41-ct Dresden Green diamond is the largest, and perhaps the finest, green diamond known to have a color of natural origin. A diamond so rich in history is well worth studying for ...
This article examines the sophisticated techniques and equipment currently used to fashion a polished gem from a rough diamond. The basic manufacturing techniques— sawing, bruting, blocking, and ...
Results from spectroscopic analyses of GE POL high-pressure high-temperature (HPHT) annealed nominally type IIa diamonds are presented, and these spectral characteristics are compared with those of ...
In recent years, the obligation to fully disclose all gem treatments has changed from a mere ethical responsibility to a legal one. The U.S. Federal Trade Commission Guides for the gem and jewelry ...
Renewed interest in large-scale commercial mining of Montana sapphires motivated a detailed study of the heat treatment of sapphire from the Rock Creek deposit. During the course of this systematic ...