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.

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 ...

Reports on a visit to a shell nucleus manufacturer and two pearl farms in northern Vietnam, which is emerging as a notable producer.

While more people are becoming familiar with lab-grown diamonds, many still don’t know how they are actually made. Learn about the two diamond growth processes, HPHT and CVD.

Carbon is one of the most important elements on our planet, which led the Geological Society of London to name 2019 the Year of Carbon. Diamonds are a main host for carbon in the deep earth and also ...

Figure 1. A view of the pink sapphire mining pit at Kibuko, in the Uluguru Mountains of Tanzania. Photo by Vincent Pardieu/GIA. A team of GIA field gemologists visited Tanzanian mines in the summer of ...

A highly saturated purplish pink to red pezzottaite from a new deposit in Madagascar is encountered in Tucson and tested by GIA researchers.

Part 2 of 5 in the series: Value Factors, Design, and Cut Quality of Colored Gemstones (Non-Diamond). This article establishes a common language for discussing cutting styles, with a focus on basic ...

GIA researchers report on a new nickel-diffusion treatment used to modify color in spinel and present criteria for identification.

ABSTRACT Aquamarine and heliodor are colored by Fe ions, an important coloring agent for beryl. Blue to yellow gem beryl was studied by quantitative spectroscopy and trace-element analytical ...