Figure 1. The vivid colors seen in fine gem-quality spinel are derived from the mixing between multiple different chromophores in a range of ratios and concentrations, as in this fine 13.52 ct ...

The Diamond and Diamond Grading eLearning course brings to life the skills needed to grade the color, clarity and cut of diamonds through video, graphics, images and text.

Tanzanite is one of the most popular colored gemstones in the world.- Courtesy Tanzanite Foundation ™ Tanzanite is a versatile gemstone that comes in a variety of sizes and cutting styles. Although it ...

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Soon after it was first marketed in 1976, colorless cubic zirconia became the dominant diamond imitation, with current production of approximately 60 million carats per year. Although cubic zirconia ...

Gem-quality spessartine garnet and grossular garnet have been discovered in Altay, China. Gemological and mineralogical studies show that their properties are typical for these garnet species.

The popular GIA Graduate Jeweler program blends a foundational technical education with the practical skills needed in the modern jewelry industry while encouraging students to express their ...

Through extensive hands-on practice using gemstones, you will explore grading the color, clarity and cut quality of a wide range of colored stones. Coursework includes the study of the GIA Colored ...

For over 100 years, reference has been made to a unique sapphire, the color of a lotus blossom, the padparadscha. Yet the precise hue represented by this rare stone has been a subject of discussion, ...

Vivid blue, green, and purple-to-violet cuprian elbaites, renowned in the gem trade as “Paraíba” tourmalines, continue to be recovered in small amounts from northeastern Brazil. Since the initial ...

Many of the important gem minerals seen on today's market - aquamarine, tourmaline, and topaz, among others - come from an unusual type of rock known as a pegmatite. Gem-bearing pegmatites are ...

2月生まれの方の誕生石はアメシストです。アメシストは、何千年も人々を魅了しているクォーツの紫色の変種です。ライラックから深い紫色の色相を呈するアメシストは、多くの形やサイズ ...