Get details on the latest research from the GIA research team, including: natural diamond geology and mining locations, causes of colors and optical features, laboratory-grown diamond research, ...

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

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 ...

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 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 ...

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

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

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 ...

A chemical and spectroscopic comparison of two purple gem spinel samples, one of them the first reported example of a spinel with a saturated purple color caused predominantly by chromium and cobalt.

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 ...

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.

With the increasing use of radiation to color enhance gemstones, the issue of radioactivity has become a source of concern for gemologists worldwide.