A yellowish green specimen with horsetail-like inclusions is found to be glass rather than demantoid garnet.

Part 4 of 5 in the series "Value Factors, Design, and Cut Quality of Colored Gemstones (Non-Diamond)" digs deeper into cutters’ choices and explores additional factors used in the trade to assess relative value.

Part 5 of 5 in the series “Value Factors, Design, and Cut Quality of Colored Gemstones (Non-Diamond)” explores craftsmanship’s bearing on cut quality.

Part 3 of 5 in the series “Value Factors, Design, and Cut Quality of Colored Gemstones (Non-Diamond)” examines how cutting decisions can have a profound effect on a gemstone’s color quality.

Part 2 of 5 in the series “Value Factors, Design, and Cut Quality of Colored Gemstones (Non-Diamond)” establishes a common language for discussing cutting styles, with a focus on basic faceting styles, and offers a short discussion on cabochons and beads.

A look at the color zoning exhibited by the largest HPHT-treated blue diamond graded by GIA.

A project coordinated by GIA and the NGO Pact provides a valuable educational tool to women miners in Tanzania.

全5部の連載記事『カラー宝石（ダイヤモンド以外）の価値要因、デザイン、カットの品質』の第1部。この記事は、カラー宝石の価格に影響を与える主な価値要因について説明します。

recently identified mineral is found, in whisker-like form, in a gem-quality tanzanite host.

An overview of the Summer 2018 Gems & Gemology content.

Presents a visual guide to the growth processes and major gemological spectroscopic features of synthetic diamonds.

Analyzes the chemical composition and inclusion characteristics of this ancient artifact.

Summarizes data collected on more than 15,000 natural blue/gray/violet diamonds examined by GIA during the last decade and examines the mechanisms that produce this color range.

A look at the mining and distinguishing characteristics of this naturally vibrant blue sapphire.

Summarizes data collected on more than 15,000 natural blue/gray/violet diamonds examined by GIA during the last decade and examines the mechanisms that produce this color range.

Characterizes a suite of 40 natural brown to black diamonds from this deposit so that they can be distinguished from suspected treated black diamonds.

Examines Japanese “Kasumiga” freshwater cultured pearls, which grow in a variety of colors.

The first installment of G&G’s newest section explores how natural diamonds shed light on the mystery of water found in Earth’s deep mantle.

JDTプログラムはデザイナーに技法とテクニック、トレンドを超えるデザインを創り出す自由を与えます。