This large Australian light opal cabochon weighs 117.85 carats. Small play-of-color flashes of orange and green predominate in a pinfire pattern, with spots of a more muted blue over a grayish ...

Observations of Oval-, Pear-, and Marquise-Shaped Diamonds: Implications for Fancy Cut Grading Presents findings from observations of oval-, pear-, and marquise-shaped diamonds, laying the groundwork ...

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.

Blue diffusion-treated sapphires are becoming more prevalent than ever before. The diffusion technique, which involves the addition of color-causing chemicals during heat treatment, results in a thin ...

With a reach that spans the globe, GIA is a nonprofit institute dedicated to protecting consumers by ensuring their trust in gems and jewelry through cutting edge gemological research, rigorous ...

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 ...

Consumers know diamond from the slogan “A Diamond is Forever”. With some care considerations this is relatively true. The Asscher cut was popular decades ago and is again a very popular cut style.

Get ready to turn your inspirations into designs with the Jewelry Design course. You’ll learn drafting, shading, design theory, how to illustrate shape and form using several mediums, and more. At the ...

在今天的珠宝市场上，购买宝石级合成钻石或实验室制造钻石比以往容易多了。这让人们在对实验室制造钻石产生浓厚兴趣的同时，也让大家产生了顾虑：宝石学家或宝石学鉴定所能否鉴定这类钻石？ 过去 30 年间，GIA 对实验室制造钻石或人造钻石进行了广泛 ...

Asterism in peridot is a rare treat that has been reported on occasionally (S. Borg, “An unusual star peridot,” Journal of Gemmology, Vol. 17, No. 1, 1980, pp. 1–4; Summer 2009 Lab Notes, pp. 138–139) ...

图 1：提交进行常规鉴定的两颗珍珠的外观（侧坐及沿钻孔方向）。 简介 两颗珍珠被提交至 GIA 曼谷鉴定所进行常规宝石鉴定（图 1），接洽这项工作的宝石学家发现了它们的一个内部秘密，因此，这项工作很快变得既有趣而又让人略感不适。本文详细介绍了所 ...

Figure 1. This 2.07 ct oval brilliant is the first faceted milarite examined by the Carlsbad lab. Photo by Diego Sanchez. Recently the Carlsbad lab received a light yellow 2.07 ct unknown gemstone ...