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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

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 ...

GIA ダイヤモンド オリジン レポート: 科学に基づくトレーサビリティ 消費者は、これまで以上に持続可能かつ倫理的に調達された製品に対する意識を高めています。 GIA ダイヤモンド オリジン レポートは、科学的評価を使用して、ダイヤモンドの地理的起源を確認します。 詳細（英語のみ） ...

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 Knowledge Sessions are a series of talks and seminars that engage participants in the most diverse and pressing issues in gemology today, including gemstone origin, laboratory-grown stones and ...