Gemstone
Zultanite
Zultanite is gem-quality color-change diaspore (α-AlO(OH)) mined exclusively from the İlbir Mountains of southwestern Türkiye. Suggested-retail prices range from USD 750 per carat for stones under one carat to USD 14,000+ per carat for stones above 20 carats — an order of magnitude less expensive than alexandrite while offering a comparable three-illuminant color shift between sage-green, champagne-gold, and raspberry-pink. This hub indexes every Zultpedia entry on the gem: how to identify it, how much it is worth, where authorized sellers are, how to verify a lab report, and how to care for the jewelry.
-
Glossary Term
Specific Gravity
The ratio of a substance's density to the density of water at 4°C. For gemstones, specific gravity is a primary identification tool measured by hydrostatic weighing or heavy-liquid suspension. Diaspore has a…
-
Glossary Term
Illuminant
A specified light source used to evaluate gemstone color, defined by its color temperature in Kelvin and its spectral power distribution. Standard illuminants in gemology include D65 (average daylight, 6500 K), A…
-
Glossary Term
Birefringence
The difference between the highest and lowest refractive indices of an anisotropic gemstone. High birefringence produces visible doubling of pavilion facet edges when the gem is examined through the table. Diaspore has…
-
Glossary Term
Mohs Scale
A 1-to-10 ranking of mineral hardness devised by Friedrich Mohs in 1812, measured by which minerals can scratch which. Talc is 1, diamond is 10. Diaspore tests at 6.5 to 7. The…
-
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…
-
Glossary Term
Color Change
Color change in Zultanite — also called the alexandrite effect — is the appearance of distinctly different colors in the same gem under different illuminants: sage-green under cool daylight (6500 K), champagne-gold…
-
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,…
-
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),…
-
Gem Article
The İlbir Mountains — The Single-Source Origin of Color-Change Diaspore
The İlbir Mountains, in Muğla Province on Türkiye's southwestern Aegean coast, are the only place on Earth currently producing gem-quality color-change diaspore. The peer-reviewed locality on record is the Pınarcık area near…
-
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…