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Spiral structure in a Colombian emerald
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Amazing synthetic flame-fusion synthetic colour-change sapphire seen under laser excitation
Micrographs

Synthetic flame-fusion synthetic colour-change sapphire seen under laser excitation

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HPHT synthetic yellow diamond, luminescence under strong SWUV irradiation
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HPHT synthetic yellow diamond, luminescence under strong SWUV irradiation

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Pyramidal tops of quartz embedded in beige chalcedony
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Pyramidal tops of quartz embedded in beige chalcedony

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Happy Birthday, GemAlliance
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Happy Birthday, GemAlliance!

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High-temperature heated blue sapphire from Sri Lanka
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High-temperature heated blue sapphire from Sri Lanka

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A "Maltese Cross" pattern seen in a natural diamond viewed with GGTL DFI System
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A "Maltese Cross" pattern seen in a natural diamond viewed with GGTL DFI System

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Naturally healed fracture, with residual liquid film and negative crystal with altered inclusion in a purplish red sapphire from Sri Lanka
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Naturally healed fracture, with residual liquid film and negative crystal with altered inclusion in a purplish red sapphire from Sri Lanka.

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The heat treatment of corundum at Moderate temperature
Micrographs, Publication

The heat treatment of corundum at Moderate temperature

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Turquoise crystals, Beauvoir, Echassière, Ebreuil, Allier-Auvergne, France
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Turquoise crystals, Beauvoir, Echassière, Ebreuil, Allier-Auvergne, France

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GGTL Certificates
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From now, all GGTL reports will be exclusively in English.

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Precious corals, C. rubrum, P. elatius, C. japonicum, C. konojoi, H. laauense, Coll. SGDF, Photograph M.Rondeau
Publication

Review and update of the classification of precious corals.

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Dendritic inclusions (mode of formation unknown) in an unheated dark blue magmatic-related sapphire
Micrographs

Dendritic inclusions in an unheated magmatic-related sapphire from Attapeu province, South Laos

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