Winter 2015 - Volume 51, Issue 4
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13.09 ct Fancy yellow rough diamond
Very Large Type Ib Natural Diamond

A 13.09 ct. Fancy yellow rough diamond, with C centers causing the intense color, is seen in the New York lab.

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2.51 and 3.23 ct CVD synthetic diamonds
Two Large CVD-Grown Synthetic Diamonds Tested by GIA

Two near-colorless rounds, weighing 3.23 and 2.51 ct, were the largest CVD-grown synthetic diamonds GIA has examined.

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0.95 ct pearl shown on loupe.
A Natural Pearl with an Intriguing Internal Structure

A semi-baroque pearl with an unusual radial feature is submitted to the Bangkok lab for testing.

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Japanese hyalite in daylight and short-wave UV light.
Uranium Contents of Hyalite

The fluorescence of hyalite from Zacatecas, Mexico is examined and compared to material from other locations in GIA’s Tokyo lab.

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Natural Fancy pink diamond with apparent HPHT synthetic growth structure.
Treated Pink Diamond with HPHT Synthetic Growth Structure

A Fancy pink type IIa diamond showing cuboctahedral growth and greenish blue phosphorescence is shown to be a natural, treated colored diamond.

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Fossilized pearls attached to their host shell.
Large Natural Fossil Blister Pearls from Tridacna (Giant Clam) Species

Two blister pearls attached to a host shell believed to have fossilized during the later Pleistocene period and discovered in southeastern Kenya are studied.

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Synthetic quartz bangle examined in Bangkok.
Synthetic Rock Crystal Quartz Bangle with Unusual Inclusions

A high-quality bangle with two-phase inclusions, similar to natural quartz is found to be synthetic material.

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Large natural pearls from Spondylus and Trochoidea species mollusks.
Two Large Natural Pearls Reportedly from Spondylus and Trochoidea Species Mollusks

Natural pearls of unusual size and unique appearance are retrieved from the west coast of Mexico and examined in GIA’s New York lab.

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Fancy brownish greenish yellow diamond with octahedral-shaped inclusion.
Graphite Inclusions Forming Octahedral Outline in Diamond

An inclusion outlined by minute graphite crystals within a diamond create an octahedral shape.

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