The distinction of natural from cultured pearls traditionally has been based on X-radiography.

A large natural pearl discovered in an edible oyster offers insight to the scientific pearl community.

The centerpiece of this brooch is a 98.67 ct Melo pearl, believed to be one of the world's largest.

Transparent rhodonite is considered one of the most difficult of all gems to facet because of its perfect cleavage and brittle, uneven fracture.

Reports on a newly discovered treatment process for producing a deep blue color in natural spinel and proposes identification criteria.

The unique mineralogical and gemological character of gem-quality red beryl from Utah.

The February 2012 discovery of high-quality blue sapphires at Thammannawa near Kataragama in southeastern Sri Lanka has intensified gem mining and exploration in the surrounding area and all over the country.

Offers a comprehensive look at a variety of augite from Dong Nai, Vietnam, detailing its formation and gemological characteristics.

An unusually large cultured pearl was filled with multiple cultured pearls, perhaps after the emergence of an original single-bead nucleus.

Diamond formed at incredible depth shows evidence of radioactive fluids in cavities surrounded by green fluorescence halos.

The examination of two unusual garnets results in identifications issued for the first time in GIA's colored stone report records.

Studies the effects of low-temperature heat treatment on inclusions in this gem material, as well as the use of FTIR spectroscopy to detect the treatment.

Shows the conversion of limonitic residues to hematite in surface-reaching inclusions, a practical indication of heat-treated corundum.

Zircon inclusions in sapphires from Madagascar were studied to investigate the effects of heat treatment on their gemological and spectroscopic features.

Unusually large top-quality faceted Russian demantoid garnets with the characteristic lovely green to yellowish green color excite attention at the Tucson GJX show.