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An Introduction to Photoluminescence Spectroscopy for Diamond and Its Applications in Gemmology

Presents the underlying physics and methodology of this analytical technique, which has become an essential tool in identifying treated and synthetic diamonds.

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Three pieces of labradorite with yellow, blue and green flashes of color.
Article
Optical Effects of Phenomenal Cabochons

Learn how the structure, inclusions and properties of some gemstones interact with light to create unusual visual effects.

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Article
GIA's Gübelin Gem Project: Corundum

Ruby and sapphire (usually blue, but also in every other colour) have been the most important coloured gemstones for several thousand years. Originating historically in south-east and central Asia, and more recently in eastern Africa, these coloured varieties of the mineral corundum have been much sought as gems because of their rarity, colour and durability. Gem corundum can display asterism and chatoyancy due to the presence of oriented mineral inclusions, and in some cases, a change of colour when viewed under different light sources.

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GIA's Gübelin Gem Project: Spinel

Found in nearly every colour – most notably red, pink and blue – spinels are popular gemstones because of their abundance, moderate cost and attractiveness.

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Article
GIA's Gübelin Gem Project: Various Gems, Taaffeite - Zoisite

Among the collection assembled by Dr Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

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GIA's Gübelin Gem Project: Various Gems, Sapphirine - Stibiotantalite

Among the collection assembled by Dr Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

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Article
GIA's Gübelin Gem Project: Various Gems, Olivine - Rutile

Among the collection assembled by Dr Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

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GIA's Gübelin Gem Project: Various Gems, Kornerupine - Natrolite

Among the collection assembled by Dr Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

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Article
GIA's Gübelin Gem Project: Various Gems, Danburite – Humite

Among the collection assembled by Dr Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

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Article
GIA's Gübelin Gem Project: Various Gems, Barite - Cuprite

Among the collection assembled by Dr Edward Gübelin are a number of uncommon gemstones from many worldwide localities.

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