Provides a visual guide to the internal features of natural, treated, synthetic, and imitation opal.

The history of Baja California has been closely tied to the exploitation of pearls since the 16th century.

This article presents information about the CVD process, the history of its development, and properties that differentiate the resulting synthetic crystals from natural diamond.

Eight decades after the Cullinan diamond was mined, a team of gemologists examined the two famous gems that were created from it to become part of the Crown Jewels of England.

The island of Borneo is one of the oldest known —and least reported on—sources of diamonds. Although diamond mining historically was concentrated in the western area of what is now Kalimantan, recent ...

The distinction of natural from cultured pearls traditionally has been based on X-radiography. X-ray computed microtomography (μ-CT) has recently been applied to gain more insight into pearl ...

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 ...

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. ABSTRACT While virtually all gemological texts ...

This study investigated the effectiveness of a handheld magnet in detecting synthetic diamonds. A total of 104 synthetic diamonds from nine different manufacturing sources were tested. Of the ...

With the withdrawal of Soviet troops from Afghanistan, villagers in the Panjshir Valley are turning their attention to the emerald riches of the nearby Hindu Kush Mountains.

Political upheavals and technological advances, as well as changes in social and governmental attitudes and initiatives, have produced major and ongoing changes in the diamond industry.

Field Report Gems & Gemology, Fall 2016, Vol. 52, No. 3 Bead-Cultured and Non-Bead-Cultured Pearls from Lombok, Indonesia Nicholas Sturman, Jeffery Bergman, Julie Poli, Artitaya Homkrajae, Areeya ...