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

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 ...

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 ...

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.

A large number of natural-color yellow diamonds are analyzed using grading and appearance aspects among other characteristics to clarify the differences between them and the light yellow diamonds ...

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

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

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 ...

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 ...

Sri Lanka’s gemstone and jewelry industry blends traditional practices and experience with the needs of the modern global market. Photo by Andrew Lucas/GIA. To visit Sri Lanka is to experience one of ...

After documenting tourmaline production at the famous Cruzeiro mine in Brazil, GIA takes you to China, where you can witness the cutting of these stones for entry into the hottest tourmaline market in ...