Once a stone is submitted, client information is withheld from the non-client-facing staff who conduct the analysis. This measure helps ensure an unbiased report. Before undergoing examination, each ...

Of all the sapphire deposits found in Montana, the richest is in the Rock Creek (Gem Mountain) district. Between 1890 and the 1930s, over 65 tonnes of rough sapphire were recovered from this area and ...

Earth’s surface is divided into tectonic plates, and the ones that make up the ocean floor are destined to sink. Sheets of oceanic crust typically bend and sink down into Earth’s interior at so-called ...

Cuprian (copper-bearing) tourmaline, known as “Paraíba” tourmaline in the trade, has been an important gem since its discovery in 1989. Until now, almost all of the material reported has been ...

Fossicking is a special type of mining activity that Australians love. Australia is a large country rich in many types of gem resources. Come to Australia with the GIA field gemology team to feel the ...

Insight into amethyst mining activity in Morocco. Characteristic “hourglass” color zoning (figure 1) and striking red hematite “finger” inclusions help distinguish Moroccan amethyst. Although amethyst ...

Intriguing Sapphire from Montana, a New Source of Emerald in Central China, and Arkansas Turquoise Duncan Pay, Editor-in-Chief Reports on a new source of primary gem-quality sapphire from Montana, ...

Yusuke Katsurada, Ziyin Sun, Christopher M. Breeding, and Barbara L. Dutrow ...

Like the white opal, the black opal is found at the contact zone between the volcanic rock series and the underlying clay-rich layer (figure 2). The layer is one in a sequence of repeating volcanic ...

A theoretically pure and defect-free diamond would be completely colorless, and a unique attribute would be its transparency (or lack of light absorption) across a wide portion of the electromagnetic ...

The following guide will give a short description of the treatment process, some gems for which the process is used, how easy or difficult the treatment is to detect for a trained gemologist, how ...

Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or difficulty with which one mineral can be scratched by another. But the Mohs scale is deceptive.