This large Australian light opal cabochon weighs 117.85 carats. Small play-of-color flashes of orange and green predominate in a pinfire pattern, with spots of a more muted blue over a grayish ...

Harness the power of knowledge with the industry-leading instruments that GIA uses in its grading laboratories. Representing more than 85 years of research and the combined expertise of GIA’s ...

Pink-to-red coral has a long history as an ornamental gem material in jewelry, carvings, and sculptures. However, due to a variety of environmental and legal factors, the supply of high-quality, ...

GIA will offer convenient access for colored stone identification and identification and origin laboratory services at the show. Drop off your stones for expert analysis and report services in the ...

CARLSBAD, California – January 14, 2025 - The Gemological Institute of America (GIA) has announced the planned retirement of its president and CEO, Susan Jacques, at the end of 2025. The Institute has ...

This sapphire from Kashmir has an intense velvety blue color. – Photo: Robert Weldon/GIA. Sapphire is one of the Big three of jewelry colored gemstones—the other two are ruby and emerald. A durable ...

Make sure your invoice specifies that the spinel you are buying is natural. If you have any doubt, a report from the GIA lab will confirm whether a spinel is natural.

ルビーは7月の誕生石で、最も人気の高い宝石の一つです。ルビーという名称は、愛と情熱の色である「赤」という意味を持つラテン語の「ruber」に由来します。ルビーの誕生石ほど目をひく ...

Established in 1931, the Gemological Institute of America (GIA) is the world’s foremost authority on diamonds, colored stones, and pearls. A public benefit, nonprofit institute, GIA is the leading ...

A GIA Report is not a guarantee, valuation or appraisal, and GIA makes no representation or warranty regarding its Reports, the articles described therein or any inscription thereon. A GIA Report ...

Figure 1. A single tourmaline fiber contains three distinct chemical zones, each recording the fluid composition at the time of growth. Between zones, fluids dissolved preexisting tourmaline to ...

Heating is an accepted treatment for sapphire. But for fine-quality sapphire, confirmation from an independent laboratory like GIA that there is no evidence of heat adds to a sapphire’s rarity and ...