This chart focuses primarily on the types of natural inclusions found in tourmaline, as well as the minerals in which tourmaline can be found as an inclusion. Treatments such as enhancement of ...

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. Sapphires from a variety of sources. Faceted stones (left to right): 6.36 ct pink/orange (padparadscha), 1.63 ct pink, 4.76 ct violet, 5.43 ct violet purple, 3.03 ct blue, 2.12 ct blue, 8.06 ...

Diamond “type” is a concept that is frequently mentioned in the gemological literature, but its relevance to the practicing gemologist is rarely discussed. Diamonds are broadly divided into two types ...

A new opal deposit was discovered in 2008 near the village of Wegel Tena, in volcanic rocks of Ethiopia’s Wollo Province. Unlike previous Ethiopian opals, the new material is mostly white, with some ...

This amethyst crystal is from Namibia. It shows classic quartz crystal shape: a six-sided columnar crystal with a pyramid-shaped termination at the top. Courtesy Daniel Trinchillo, Fine Minerals ...

Figure 1. Schematic representation comparing PL methods. With standard PL microscopy, a single spot (shown as a green circle in the figure) is analyzed and represents only a small volume of the actual ...

Lapis lazuli is an aggregate of several minerals. Lazurite grains provide its characteristic blue color, while golden flakes of pyrite can add attractive contrast. Lapis lazuli is a rock, which means ...

The GIA Gem Trade Laboratory (GTL) collected gemological data on 1,490 natural-color pink gem diamonds—both types I and II. While there was some overlap in gemological properties between the two ...

Gemological and spectroscopic properties of CVD synthetic diamonds from Gemesis Corp. were examined. Their color (colorless, near-colorless, and faint, ranging from F to L) and clarity (typically VVS) ...

Malaya garnets from Bekily, Madagascar, are predominantly pink to pinkish orange, with some stones orange to red. Discovered only in the late 1990s, the majority are intermediate members of the pyrope ...

Descending into Peshawar for the first time, a foreign tourist might be surprised to learn that amid the clutter of buildings in this historical city lies an important gem trading center. This market ...