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Brown-orange treated CVD-grown synthetic diamond.
Fancy Deep Brown-Orange CVD Synthetic Diamond

A CVD-grown diamond shows an unexpected treatment-caused color.

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Diamond before and after filling large fractures.
Fracture-Filled Diamond with "Rainbow" Flash Effect

The material used to fill a large fracture in a diamond yields an unexpected iridescence under two different illuminations.

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Turquoise bead with artificial metallic pyrite.
Turquoise with Simulated Matrix

A turquoise bead is found to have an artificial pyrite and resin matrix.

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Opal slices before and after water immersion
Hydrophane Opal Treatment

An opal rough is immersed in water and treated with oil and Opticon to observe effects on transparency and play-of-color.

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59.88 ct Fancy Vivid yellow irradiated diamond
Very Large Artificially Irradiated Yellow Diamond

Examination of a 59.88 ct irradiated yellow diamond, one of the largest irradiated diamonds identified by GIA.

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4.29 ct color-treated Fancy brown-pink diamond
Treated Pink Type IIa Diamond Colored by Red Luminescence

A type IIa color-treated diamond was graded as Fancy brown-pink under daylight conditions and Fancy purplish gray under incandescent lighting, a color change that resulted from HPHT annealing and irradiation.

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DiamondView image of pink diamond showing two pink spots near the edge of the table facet
Evidence of Focused Beam Irradiation in Treated Pink Diamond

DiamondView imaging and photoluminescence spectroscopy offered evidence of focused beam irradiation in a pink diamond.

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Black star sapphire enhanced with lead glass
Lead Glass–Filled Black Star Sapphire

The first example of a lead glass–filled black star sapphire examined at GIA’s New York laboratory.

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Fancy red and Fancy Vivid yellowish green color-treated synthetic diamonds
Treated Red and Green HPHT Synthetic Diamonds

Two treated synthetic diamonds, a Fancy red and a Fancy Vivid yellowish green, showed strikingly vibrant colors.

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Emerald with two drill holes
Unique Drilled Emerald

An emerald with drill holes containing a resinous material is seen in the New York lab.

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