Citrine is one of the most popular yellow gems on the market. This designer cut shows off the warm glow of citrine’s sunny color. – Lydia Dyer, gem courtesy John Dyer & Co. Citrine—the transparent, ...

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 ...

GIA 远程教学包含网络学习和实习班。 网络学习是指在线进行课程学习 — 课程材料在线提供，作业和期末考试在线进行。 在实习班，您可以和讲师一起分级和鉴定宝石，获得必要的实践经验。 查看世界各地的 GIA 校区提供的实习班课程。 可在以下页面中找到 ...

The People's Republic of China has recently placed a high priority on identifying and developing its gemstone resources. Initial exploration by teams of geologists throughout China has identified many ...

Quartz crystals containing stellate tufts of silvery gray rutile were recently discovered in east-central California. Photomicrograph by Nathan Renfro; field of view 9.48 mm. Recently, author JG ...

Figure 1. A single tourmaline fiber contains three distinct chemical zones, each recording the fluid composition at the time of growth. Between zones, fluids dissolved preexisting tourmaline to ...

The September birthstone is sapphire – a gem that’s been cherished for thousands of years. Although the term sapphire usually refers to the blue variety of corundum (ruby is the red variety), this ...

A synthetic gem material is one that is made in a laboratory, but which shares virtually all chemical, optical, and physical characteristics of its natural mineral counterpart, though in some cases, ...

Diamond is available in a range of sizes and qualities to fit every consumer's tastes. One of the first things most people learn about diamonds is that not all diamonds are created equal. In fact, ...

As a consumer, you will regularly encounter in the marketplace gems that have been treated to change their appearance. A topic that often comes up is whether a particular gemstone is or isn’t treated.

This 5.30-carat emerald from Brazil has a slightly bluish green color. Courtesy John Parrish, courtesy African, Brazilian, Colombian Gems Incorporated. Emerald has many special qualities, but colored ...

The 97.45-carat Blaze Imperial Topaz is in the collection of the Field Museum of Natural History. - Courtesy "Gems and Gemstones: Timeless Natural Beauty of the Mineral World" by Grande & Augustyn, U ...