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

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

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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
Micrographs

HPHT synthetic yellow diamond, luminescence under strong SWUV irradiation

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Pyramidal tops of quartz embedded in beige chalcedony
Micrographs

Pyramidal tops of quartz embedded in beige chalcedony

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Happy Birthday, GemAlliance
Insight

Happy Birthday, GemAlliance!

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High-temperature heated blue sapphire from Sri Lanka
Micrographs

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
Insight, Micrographs

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
Micrographs

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, Research

The heat treatment of corundum at Moderate temperature

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

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

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GGTL Certificates
Insight

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
Research

Review and update of the classification of precious corals.

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