Research Article Search Results

Since late 2007, rubies and sapphires have been mined by hand methods from both eluvial and primary deposits at Winza in central Tanzania.

The finest and rarest emeralds are sometimes said to have an optical effect called gota de aceite.

High-quality CVD-grown diamonds, comparable in color and clarity to natural diamonds, can be identified using a combination of gemological and spectroscopic properties.

In early 2004, the GAAJ laboratory in Japan issued a lab alert about rubies they had seen that had large numbers of fractures filled with high-lead-content glass, which made them appear very transparent.

Zambia is considered the world’s second most important source of emeralds by value (after Colombia).

A new chart, supplementing the one published in the Winter 1995 issue of Gems & Gemology, summarizes the features of both as-grown (“non-modified”) and treated (“modified”) synthetic diamonds currently in the gem market (that is, those grown by the high pressure/high temperature technique).

The GIA diamond cut grading system described here includes the components of brightness, fire, scintillation, polish, and symmetry, as well as weight and durability concerns, into a single overall grade for cut quality for standard round brilliants.

Australia’s Argyle mine has set records for volume since its establishment in 1983, and is additionally noted for its rare pink diamonds.

Since 1993, large amounts of gem-quality sapphires from the Andranondambo region of southern Madagascar have entered the international gem market.

This article illustrates the various features in filled diamonds and explores the best techniques for examining them.

Yogo Gulch, discovered more than 100 years ago, is one of four major sapphire-producing areas in Montana, United States.

Renewed interest in large-scale commercial mining of Montana sapphires motivated a detailed study of the heat treatment of sapphire from the Rock Creek deposit.