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.

Figure 1. Pleochroism in a 15 ct tanzanite, as seen with the unaided eye through the crown and the pavilion sides and ends. Photo by Wimon Manorotkul. In describing colored gemstones, the major ...

「GIAの社長兼CEOであるスーザン・ジャックは、6月2日（金）にJCKラスベガスショーで発表された、初のGIA（米国宝石学会）サステナビリティレポートについて、「私たちが事業を行う環境、社会、地域社会に与える影響を理解することは、私たちが掲げる ...

以莫氏硬度衡量宝石和矿物的硬度。 这些数值基于一种矿物可被其他物品划伤的相对难易程度得出。 但莫氏硬度易产生误导。 矿物之间的等级差距并不相等。 举例来说，钻石仅比刚玉高一个等级，但其硬度却比刚玉坚硬许多倍。 碧玺在莫氏硬度表上居 7 至 7.5。

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, ...

If you were born in the month of June, you are lucky enough to have three birthstones to call your own. June is one of only three months (the others are August and December) that has three birthstones ...

Such innocuous events as the creation of the pre-gummed envelope and the modem postal system contributed to the demise of the engraved gem seal. During the thousands of years that the seal served as ...

这颗大型澳大利亚淡色凸圆面蛋白石，重达 117.85 克拉。蛋白石上面布满了橙色和绿色的星火图案小型游彩闪光，灰色的体色缀以柔和的蓝色斑点。 每一颗蛋白石的外观和质量都大有不同。正如雪花和指纹一样，每颗宝石都有明显的差异。 蛋白石评估应在可控 ...

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 ...

这颗年代久远的华丽垫型切工橄榄石重 130.60 克拉有宝石最优良的属性：中等深度的色调、高饱和度的黄绿色彩以及高净度。 橄榄石可用于多种类型的珠宝。 即使是一般商业质量的橄榄石，也可以是实惠而又有吸引力的。 橄榄石也可以是大尺寸和非常强烈的 ...

合成宝石材料是在实验室中制成的一种材料，但却具有与其相对应的天然矿物相同的化学、光学和物理特性，虽然在某些情况下，如合成土耳其石和合成蛋白石，可能会有其他化合物的存在。 自 19 世纪后期以来，就已经开始生产合成宝石晶体，其产品往往是 ...

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 ...