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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Gem Article
The Lapidary of Zultanite — Why 97% of the Rough Is Lost in Cutting
Cutting Zultanite costs about 97% of the rough crystal's weight, according to the trademark holder Zultanite Gems LLC. The reason is mineralogical: gem-quality diaspore has perfect cleavage on the {010} plane, so…
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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…