Topic
Identification
Identification entries on Zultpedia cover how to distinguish genuine Türkiye-source color-change diaspore from synthetic color-change sapphire, color-change garnet, color-change fluorite, and other-locality natural diaspore. Includes the field-test protocol, dichroscope and refractometer use, lab-report interpretation, and laboratory-grade trace-element analysis (LA-ICP-MS).
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Gem Article
The Trace-Element Chemistry of Zultanite — Iron, Chromium, and the Color-Change Mechanism
Zultanite's color change is produced by trace iron (Fe³⁺) substituting into the aluminum site of the diaspore lattice, with chromium (Cr³⁺) contributing additional absorption in the red region. The combined absorption spectrum…
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Property Guide
Specific Gravity of Zultanite — 3.30 to 3.39
Zultanite (gem-quality color-change diaspore) has a specific gravity of approximately 3.30 to 3.39, depending on trace-element content. It is heavier than quartz (2.65) and tourmaline (3.06), comparable to topaz (3.49–3.57), and lighter…
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Property Guide
Color Change of Zultanite — Three Illuminants, One Crystal
Zultanite shifts visible color across three illuminants: sage-green under cool daylight (6500 K), champagne-gold under indoor incandescent or fluorescent light (~3000 K), and raspberry-pink under candlelight (~1850 K). The shift is caused…
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Property Guide
Pleochroism of Zultanite — Three Crystallographic Colors
Zultanite shows strong trichroic pleochroism: it displays three different colors when viewed along its three principal crystallographic axes. Typical pleochroic colors are kiwi-green, dark green-brown, and pinkish-orange. This is independent of the…
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Property Guide
Refractive Index of Zultanite — 1.682 to 1.752
Zultanite (gem-quality color-change diaspore) has a refractive index range of 1.682 to 1.752 with strong birefringence (~0.048). It is a biaxial positive gem with three distinct refractive indices: nα 1.682–1.706, nβ 1.705–1.725,…
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Glossary Term
Pleochroism
Pleochroism is the appearance of different colors when an anisotropic crystal is viewed along different optical axes under the same light. It is a property of the crystals internal symmetry, not of…
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FAQ Cluster
Zultanite — Frequently Asked Questions
Frequently asked questions about Zultanite — gem-quality color-change diaspore from the İlbir Mountains of Türkiye. Twenty Q&A pairs covering identity, rarity, sourcing, color, jewelry use, and buying guidance. Sourced from peer-reviewed mineralogy,…
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Gem Comparison
Zultanite vs Alexandrite — Two Gems, One Phenomenon, Different Propositions
Zultanite (color-change diaspore) and alexandrite (color-change chrysoberyl) are mineralogically unrelated species that produce a similar visual phenomenon — the alexandrite effect — through different chemistries. Alexandrite is harder (8.5 vs 6.5–7 Mohs),…
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Gem Article
The Color-Change Phenomenon in Zultanite — How and Why It Works
The color-change phenomenon in Zultanite — properly called the alexandrite effect — is a perceptual outcome of selective light absorption, not a property of the stone changing. Trace iron and chromium ions…
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Gem Article
What Is Zultanite? The Color-Change Diaspore from Türkiye
Zultanite is a registered trade name for gem-quality color-change diaspore — α-AlO(OH) — mined exclusively in the İlbir Mountains of southwestern Türkiye. The same material is sold under the parallel trade names…