一月生日石柘榴石是品种最丰富的宝石之一，因为它有许多不同的颜色。柘榴石生日石可在世界各地进行开采，象征着许多不同的乐观情绪。了解更多关于这种独特生日石的信息。 紫水晶是二月 ...

This sapphire from Kashmir has an intense velvety blue color. – Photo: Robert Weldon/GIA. Sapphire is one of the Big three of jewelry colored gemstones—the other two are ruby and emerald. A durable ...

To address concerns about laboratory-grown and treated diamonds being mixed into parcels of melee, GIA has developed an automated system to analyze and sort melee-size diamonds quickly and accurately.

This 146.10-carat peridot is in the collection of the Natural History Museum in London Peridot has always been associated with light. In fact, the Egyptians called it the “gem of the sun.” Some ...

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 ...

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.

We grade only loose diamonds because a mounting or setting can obscure or influence the color and clarity grade and make it difficult to determine an exact carat weight. Grading loose stones also ...

GIA studied more than 400 important gemstones from the Gübelin Collection and is committed to sharing this repository of gemological information. This work is a valuable resource for all students, ...

这颗晶体显示出供其生长的母岩的痕迹。 优质丹泉石有很强的多向色，且正面呈现鲜艳的紫到蓝色，这两种特点有助于鉴定宝石，也对宝石的价值有很大的影响。颜色较暗淡的宝石更为常见 ...

Jadeite comes in a wide range of colors. The most valuable is an intense green called Imperial. - Courtesy Mason-Kay Fine Jade Jewelry To understand the value of jade, you have to look beyond its ...

Heating is an accepted treatment for sapphire. But for fine-quality sapphire, confirmation from an independent laboratory like GIA that there is no evidence of heat adds to a sapphire’s rarity and ...