The Absorption Spectrum of Color-Change Diaspore

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Gem Article

The Absorption Spectrum of Color-Change Diaspore

Diaspore
5 min read Fact-checked 2026-04-27

Color-change diaspore from the İlbir Mountains shows a characteristic UV-Vis-NIR absorption profile dominated by trace iron (Fe³⁺ band near 425 nm) and trace chromium (Cr³⁺-related broad absorption centered near 580 nm). Transmission windows in the green and red regions of the visible spectrum are what produce the alexandrite effect: under daylight (rich in green wavelengths) the gem reads sage; under candlelight (rich in red) it reads raspberry.

The verified facts

This entry is part of the Zultpedia editorial archive on color-change diaspore from the İlbir Mountains of southwestern Türkiye. Mineral species: diaspore (α-AlO(OH)). Hardness: 6.5–7 Mohs. Refractive index: 1.682–1.752. Specific gravity: 3.30–3.39. The verified mineralogical baseline is documented across the property guides; the citations beneath this entry trace each claim to its primary source.

Editorial framing

Zultpedia treats color-change diaspore as a single-source mineral species first and a trade-name commodity second. The trade names Zultanite®, Csarite, Ottomanite, and Turkizite all refer to the same gem from the same locality; mineralogical claims apply equally to all four.

Cross-references

See also the related entries listed beneath this article and the property guides for verified physical and optical values.