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 ...

7.9-cm tall crystal. Both are from Sappat, Kohistan, Pakistan. - Jeffrey Scovil Gem miners find peridot as irregular nodules (rounded rocks with peridot crystals inside) in some lava flows in the ...

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, ...

A baroque pearl forms the body of a Triton in this jewel. © Victoria and Albert Museum, London. People have coveted natural pearls as symbols of wealth and status ...

A 43-carat alexandrite in the collection of the British Museum. Abundant alexandrite deposits were first discovered in 1830 in Russia’s Ural Mountains. Those first alexandrites were of very fine ...

The GIA Diamond Grading Report includes an assessment of the 4Cs – Color, Clarity, Cut, and Carat Weight – along with a plotted diagram of its clarity characteristics and a graphic representation of ...

There are many jewelry trade associations located throughout the world. This list is not comprehensive. Many regional groups will be found under their main association like Jewelers of America or the ...

The red and green dyes in this bracelet’s amber pieces can fade over time. Hardness and toughness Gem and mineral hardness is measured on the Mohs scale. The numbers are based on the relative ease or ...

As an international jewelry hub and world destination commercial center, Hong Kong is the quintessential location for the gem and jewelry sector. Combine that with educational powerhouse GIA, and you ...

瑞々しい青、鮮やかなバイオレット、濃い紫色のバランスを整えたエキゾチックなタンザナイトが発見される場所は、地球上でただ一つ、雄大なキリマンジャロ山の近くにあります。 タンザナイトの豊かな色相はサファイアの美しさに匹敵するほどです。

详情：数量、重量、大小、形状、颜色、产地、软体动物、环境和可查明的处理方式。 鉴定未镶嵌、镶嵌珍珠或珠串。 包括所有鉴定证书信息，加上光泽、表面和匹配（如适用）。 鉴定未镶嵌、镶嵌或珠串珍珠。 包括基于 GIA 7 Pearl Value Factors™ (GIA 珍珠品质 ...