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 ...

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 ...

Diamonds have a long history as beautiful objects of desire. In the first century AD, the Roman naturalist Pliny stated: “Diamond is the most valuable, not only of precious stones, but of all things ...

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. The color zoning of amethyst from Boudi often displays a characteristic hourglass shape. Photo by Abdelghani El Harfi and Salahaddine Mouaddib. ABSTRACT Amethysts from Boudi, Morocco, are ...

In November 2022, a parcel of 24 approximately 0.5–1.2 ct spinel crystals, described as cobalt-diffused, were obtained directly from a treater by the research team at GIA in Bangkok. Of these, seven ...

A GIA evaluates rose quartz but does not grade it. A GIA Colored Stone Identification Report assesses the characteristics of any polished, rough, mounted or loose material (weight, measurements, shape ...

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 ...

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 ...

The GIA Report Results API allows applications to integrate with GIA’s database in order to verify grading information and retrieve GIA report PDFs, images and other assets associated with a GIA ...

Graduate Jeweler Program The Graduate Jeweler diploma program is a hands-on experience that introduces students to the knowledge and skills required for a career in jewelry fabrication and repair. You ...