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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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
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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Education Article
How Much Is Zultanite Worth? — Price and Value Guide
Zultanite — gem-quality color-change diaspore from Türkiye — has a published suggested-retail price table from Zultanite Gems LLC ranging from USD 750 per carat for stones under one carat to USD 14,000+…
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FAQ Cluster
Zultanite Price and Value — Frequently Asked Questions
Zultanite has a suggested-retail price table from Zultanite Gems LLC ranging from USD 750 per carat for stones under one carat to USD 14,000+ per carat for stones above 20 carats. Per-carat…
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Gem Comparison
Zultanite vs Csarite vs Ottomanite vs Turkizite — One Gem, Four Names
Zultanite, Csarite, Ottomanite, and Turkizite are all trade names for the same mineral — gem-quality color-change diaspore (α-AlO(OH)) from the İlbir Mountains of Türkiye. Mineralogy, source, and physical properties are identical. The…
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Gem Comparison
Zultanite vs Andalusite — Two Türkiye-Adjacent Pleochroic Gems Compared
Zultanite (color-change diaspore, 6.5–7 Mohs, RI 1.682–1.752, color-changing across three illuminants) and andalusite (Al₂SiO₅, 7–7.5 Mohs, RI 1.629–1.650, strongly pleochroic but not color-changing) are both trichroic but differ in mineral species, hardness,…
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Gem Article
The History of Color-Change Diaspore — From Haüy to the İlbir Mountains
Color-change diaspore — the mineral species — was first described by René Just Haüy in 1801 in the Mineralogie volume of his foundational works. Gem-quality material from the İlbir Mountains of southwestern…
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Gem Article
Why Zultanite Is Rare — Single Source, Cleavage Loss, and Trace Chemistry
Zultanite's rarity has three structural causes: (1) single-source origin — gem-quality color-change diaspore comes from one mountain range in Türkiye, with no comparable secondary locality in commercial production; (2) lapidary loss —…
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Gem Article
The Anatolian Heritage of Zultanite — Names, Geography, Diaspore Source
The cultural framing of Zultanite ties the gem to Anatolian heritage through three deliberate signals: the trade names (Zultanite from "sultan", Ottomanite from the Ottoman empire, Csarite from "tsar"), the source mountain…
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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…