Gemstone
Diaspore
Diaspore (α-AlO(OH)) is the mineral species, first described by René Just Haüy in 1801. While diaspore is geologically common in bauxite ore worldwide, gem-quality color-change diaspore — the alexandrite-effect variety sold as Zultanite, Csarite, Ottomanite, and Turkizite — is documented only from a single locality: the İlbir Mountains of Türkiye. Buyer prices range from USD 750 per carat to USD 14,000+ per carat depending on weight band and color-change strength. This hub indexes every Zultpedia entry on the species.
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Property Guide
Crystal Habit of Diaspore — Tabular, Acicular, Massive
Diaspore commonly forms thin platy or tabular crystals flattened on {010}, occasionally elongated needle-like (acicular) crystals along the c-axis, and frequently as fine-grained massive aggregates within bauxite ore. Gem-quality crystals from the…
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Gem Article
Export Documentation for Türkiye-Sourced Zultanite
Türkiye-sourced color-change diaspore exported for the international gem trade typically carries documentation including a Türkiye Mineralogical Heritage attestation, customs declarations citing HS code 7103 (precious and semi-precious stones), and where applicable a…
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Property Guide
Optical Character of Zultanite — Biaxial Positive
Zultanite is biaxial positive: light traveling through the crystal splits into two rays with three principal refractive indices (nα 1.682–1.706, nβ 1.705–1.725, nγ 1.730–1.752), with nβ closer to nα than to nγ.…
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FAQ Cluster
Zultanite Jewelry Care — Frequently Asked Questions
Zultanite jewelry requires gentler handling than harder gems. Clean only with warm soapy water and a soft brush. Never use ultrasonic or steam cleaners. Store separately from harder gems. Avoid daily-wear ring…
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FAQ Cluster
How to Identify Real Zultanite — Frequently Asked Questions
Identifying genuine color-change diaspore requires five tests: color change between daylight and incandescent illuminants, trichroic pleochroism via dichroscope, refractive index 1.682–1.752 with strong birefringence, specific gravity 3.30–3.39, and a recognized laboratory report…
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FAQ Cluster
Zultanite vs Other Color-Change Gems — Frequently Asked Questions
Zultanite (color-change diaspore) is one of several color-change gems on the market, each distinguished by mineral species, hardness, source region, and the strength and direction of color shift. Alexandrite (chrysoberyl) is the…
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Education Article
How to Photograph Zultanite Color Change
Photographing Zultanite color change requires three illuminant setups: daylight (D65, 6500 K), indoor incandescent (2856 K), and candlelight (~1850 K). Use a neutral-gray background, manual white balance, fixed exposure, and the same…
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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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Education Article
How to Read a GIA Zultanite Report
A GIA color-change diaspore report documents seven facts you must verify: species (must read "diaspore"), variety (must read "color-change"), weight to two decimals, dimensions, cut style, refractive index range (1.682–1.752 expected), specific…
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Education Article
How to Insure Zultanite Jewelry
Insure Zultanite jewelry through a specialty jewelry-insurance carrier (Jewelers Mutual, Chubb, BriteCo) rather than relying on a homeowner's policy, which typically caps gem coverage at $1,000–$2,500. Insure for replacement value at current…