Typically, turquoise is judged on three basic quality factors: color, texture and the presence or absence of matrix. Learn more about turquoise and what makes this gem so sought after!

Lapis lazuli is a rock, which means it’s an aggregate of several minerals. This ancient gem contains three minerals in varying amounts: lazurite, calcite, and pyrite. Sometimes, it also contains one or more of the following: diopside, amphibole, feldspar, and mica.

了解紫黄晶如此受欢迎的原因。

Tourmalines come in a wide variety of exciting colors. In fact, tourmaline has one of the widest color ranges of any gem species, occurring in various shades of virtually every hue.

GIA 第一位女性宝石学家及行业先锋。

GIA 第一位女性宝石学家及行业先锋。

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

GIA Diamond Focus® Report（钻石精要证书）是高性价比的分级证书，以数字化格式提供特定天然钻石（未处理、颜色为 D 到 Z 、重量为 0.15 至 0.39 克拉）的关键分级信息。

Learn about tanzanite's durability and how to care for your tanzanite jewelry.

GIA美国宝石研究院是一家慈善性非营利 501(c)(3) 组织，其使命是秉承诚信、学术、科学和专业精神的高标准，确保公众对宝石和珠宝的信任。

查看更新的鉴定所注意事项。

Learn about the factors that make iolite so desirable.