Topic
Spectroscopy
Spectroscopy entries on Zultpedia cover laboratory identification of color-change diaspore: UV-Vis-NIR absorption profiles (Fe³⁺ band near 425 nm, Cr³⁺-related band near 580 nm), FTIR signatures, Raman bands, and trace-element analysis used to distinguish Türkiye-source material from synthetics, simulants, and other-locality diaspore.
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Gem Article
Zultanite — Fracture-Filling and Coating Detection in Gemological Labs
Fracture-filling and surface-coating treatments are not standard for Zultanite (color-change diaspore), but laboratories test for them as part of the standard identification protocol. FTIR spectroscopy detects organic resin fillers; surface inspection under…
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Education Article
How to Spot Fake Zultanite — A Field Checklist
Five field tests rule out the common Zultanite lookalikes: (1) color change must shift fully between daylight and candlelight illuminants (synthetic sapphire shifts blue-violet, not sage-raspberry); (2) trichroic pleochroism via a $20…
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Glossary Term
UV-Vis-NIR Spectroscopy
Ultraviolet-visible-near-infrared absorption spectroscopy. The standard laboratory technique for quantifying which wavelengths a gemstone absorbs and which it transmits. Color-change diaspore shows characteristic Fe³⁺ absorption near 425 nm and a broad Cr³⁺-related band…
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Glossary Term
FTIR Spectroscopy
Fourier-transform infrared spectroscopy. A non-destructive technique that identifies a mineral's molecular fingerprint via its mid-infrared absorption bands. For diaspore, FTIR confirms the species via characteristic O-H stretching modes, distinguishing it from chemically…
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Glossary Term
LA-ICP-MS
Laser ablation inductively coupled plasma mass spectrometry. A trace-element fingerprinting technique used in modern gemological labs to attribute a stone to its geographic origin by measuring parts-per-million levels of dozens of elements.…
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Glossary Term
Fluorescence
The emission of visible light by a material when stimulated by ultraviolet radiation. Diaspore is generally inert to long-wave UV and may show weak yellow-green fluorescence under short-wave UV in some specimens.…
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Gem Article
Identifying Natural Versus Synthetic Diaspore
No commercial synthetic color-change diaspore exists in the gem trade as of 2026. Misidentification typically involves color-change synthetic sapphire, color-change garnet, or other-locality natural diaspore being sold under Türkiye trade names. Diagnostic…
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Gem Article
Lab Reports — What GIA and IGS Document for Color-Change Diaspore
A complete gemological laboratory report for color-change diaspore documents: species (diaspore), variety (gem-quality color-change), weight to two decimal places, dimensions, cut style, color description under standard illuminants D65 and A, refractive index…