A cut gemstone with intense chatoyancy that originated from Sri Lanka was determined to be a member of the scapolite solid-solution series. Indices of refraction and unit-cell dimensions were found as ...

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, ...

The separation of naturally colored lavender jadeite from color-treated material is a problem that has long plagued gemologists. One theory is that the dyeing agents being used are of an organic ...

GIA Instruments works hand-in-hand with GIA’s laboratory, education and research teams, as well as the jewelry trade to develop the instrumentation you need to prepare you for the challenges of ...

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 ...

如果您出生于六月，那么您很幸运，可以拥有三种生日石。六月是仅有的三个有三种生日石的月份之一（另外两个月份是八月和十二月），让您有各种各样美丽的生日石可以选择。 六月生日石是 ...

In an effort to help you understand the GIA Cut Grading System more fully, and to make the best use of it in your business, we provide these informative charts and booklets that summarize the system, ...

Fine-color, large, and eye-clean (lacking visible inclusions) rubies like this 11.01carat (ct) stone from Myanmar (formerly known as Burma) are extremely rare and valuable. – Photo: Robert Weldon/GIA.

Cultured pearls come in different sizes, shapes, and colors. Perhaps the best-loved gems of all time, pearls—both natural and modern cultured pearls—occur in a wide variety of colors. The most ...

橄榄石、尖晶石和褐红条纹玛瑙是三种八月生日石。众所周知，橄榄石生日石是在极端条件下形成的，可在硬化的熔岩中找到。这些岩浆从地幔深处携带橄榄石而来，也可以从来自外太空的陨石 ...

Zircon comes in a wide variety of colors. Colorless zircon is well known for its brilliance and flashes of multicolored light, called fire. These two zircon properties are close enough to the ...

Jadeite comes in a wide range of colors. The most valuable is an intense green called Imperial. - Courtesy Mason-Kay Fine Jade Jewelry To understand the value of jade, you have to look beyond its ...