GIA 与北大资源研修学院 (Peking University Resource College) 开展合作办学项目，在深圳提供校园课程、实习班和学生工作室。这些课程由 GIA 老师用中文授课。 除非另有说明，所有课程均用中文授课。 2024 年课程时间表 开课日期并不包括新生报到日 。 如需了解关于 ...

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 ...

Figure 1. Left to right: 16.73 ct, 14.50 ct, 17.03 ct, and 27.75 ct trapiche-like amethysts. The four cabochons were cut with the base perpendicular to the c-axis (optic axis). Photo by Diego Sanchez.

GIA’s D-to-Z color grading system is based on the relative absence of color. GIA’s Fancy colored diamond color grading is based on the presence of color. GIA describes color in terms of hue (the color ...

Zoltan David is an award-winning artist, and his fourteen one-of-a-kind jewelry pieces in the GIA collection are breathtaking expressions of his inspirations and design philosophies. Some of his work ...

Because yellow quartz colors are rare in nature, most citrine is the result of heating, which converts less valuable shades of purple amethyst to the golden shades of citrine.

GIA uses digital X-Radiography, as well traditional visual observation and a variety of advanced testing equipment, to determine if a pearl is natural or cultured. Microradiography is the most ...

GIA studied more than 400 important gemstones from the Gübelin Collection and is committed to sharing this repository of gemological information. This work is a valuable resource for all students, ...

However gem quality diamonds are fashioned from the original crystal shape they possess a combination of brightness, sparkle, fire, and sense of purity not matched by other gems. - Jeff Scovil, ...

To address concerns about laboratory-grown and treated diamonds being mixed into parcels of melee, GIA has developed an automated system to analyze and sort melee-size diamonds quickly and accurately.

Online courses and Lab classes required to earn your online credential offered via the GIA Online Division are listed below. Click here to download the requirements ...

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.