Blue color in aquamarine and yellow color in heliodor are attributed to abundant Fe ions (Wood and Nassau, 1968). Fe ions are also present in all other color varieties of beryl, though Fe content is ...

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 ...

In February 2024, Mark Saul (Amor Gems, Kenya) informed author VP about a sapphire rush near Matepwende village, located in the Namtumbo district in Songea, in southern Tanzania. News of a rush ...

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 ...

Investigates the morphological changes of macle diamonds during the growth process by exploring their three-dimensional internal zonal structure.

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.

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 ...

Explore pearl history, research, quality factors, and more in the GIA Gem Encyclopedia.

The Robert Mouawad Campus at GIA World Headquarters is the premier gem studies school — fully integrating state-of-the-art classrooms, the famous GIA laboratory, and an internationally recognized ...

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

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.