以下是 GIA 将休业的法定假期列表。 2025 年 5 月 5 日（星期一） 玛哈•哇集拉隆功国王陛下加冕（补假） 2025 年 5 月 12 日（星期一） 卫塞节（补假） 2025 年 6 月 3 日（星期二） 王后陛下诞辰 2025 年 7 月 10 日（星期四） 守夏节 ...

Attain your dreams of a GIA education with a scholarship. We encourage on-campus students to apply for assistance and we are happy to help you coordinate your efforts. GIA-administered scholarships ...

Resources for Careers in Gems & JewelryGIA Career Services maintains an up to date database of U.S. and international job offerings in the jewelry industry. Employers from every industry sector list ...

Opal can range from 5 to 6.5 on the Mohs hardness scale. Hardness and toughness Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with ...

Gemological LibraryResources The library provides a wide variety of gemstone-and-jewelry-related resources for students, staff, researchers, alumni, members of the industry, and the general public.

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 ...

Diamond is the only gem made of a single element: It is typically about 99.95 percent carbon. The other 0.05 percent can include one or more trace elements, which are atoms that aren’t part of the ...

GIA On Campus and accelerated programs and lab classes are available in Shenzhen through a cooperative program at Peking University Resource College. Programs and classes are taught by GIA instructors ...

Consumers know diamond from the slogan “A Diamond is Forever”. With some care considerations this is relatively true. The Asscher cut was popular decades ago and is again a very popular cut style.

In colored stones, transparency and clarity are closely linked. This is especially true for emeralds. The trade generally accepts eye-visible inclusions in higher-quality emeralds. But when the ...

Figure 1. Yellow, brownish gray, and near-colorless anorthoclase feldspar from southeast Vietnam. The rough stones range from 96.5 to 144.8 ct and the cut samples from 3.64 to 11.07 ct. Photos by Le ...

Graduate Colored Stones Online Diploma Students explore more than 60 species of common and collector gemstones found in the marketplace. Subjects covered include the GIA Colored Stone Grading System, ...