THE GEMSTONE LIBRARY
Diaspore (Zultanite)
A quiet change in the light can transform the character of a gemstone. Zultanite is a trade name associated with natural color-change diaspore, valued for delicate greens, warm champagne tones and pinkish hues. The faceted gems shown here belong to our genuine diaspore collection shared in June 2025.
What diaspore is
Diaspore is an aluminum oxide hydroxide, AlO(OH), with an orthorhombic crystal structure. Its reference hardness is 6.5–7, but it is brittle and has perfect cleavage in one direction. Hardness measures resistance to scratching; cleavage describes a direction in which a crystal can split. A stone can resist everyday abrasion yet remain vulnerable to a sharp blow.
Zultanite and the Turkish story
The name Zultanite became associated with transparent color-change diaspore from southwestern Türkiye. Published gemological accounts describe production near Pınarcık in the Muğla region and the establishment of a more consistent commercial supply in the mid-2000s. Diaspore is the mineral name; Zultanite and Csarite are trade names used for Turkish gem material. Other gem diaspore occurrences have also been reported, including Myanmar and material reportedly from Afghanistan.
Why the light matters
Color change is a response to the spectrum of the light illuminating the stone. A daylight-like source and a warmer incandescent source can produce different perceived hues. Pleochroism is a separate effect: color can also vary with the direction in which the crystal is viewed. Neither effect means that every diaspore changes by the same amount.
Research comparing diaspore and corundum examines how trace elements occupy aluminum sites and influence absorption. The presence and combination of color-producing elements help explain why diaspore can display different palettes. These published measurements provide mineralogical context; they are not chemical measurements of the photographed gems.
Looking at faceted gems
Compare a stone under more than one ordinary light source, then turn it slowly. Notice its color, the distribution of bright reflections, and any areas that remain dark. The outline and the facet arrangement both influence what you see. A photograph captures one lighting condition and one orientation, so the live experience may reveal more variation.
Genuine diaspore and imitation material
Our pictured collection is genuine diaspore. Soul Body Gems also keeps a separate educational entry for material sold as Zultanite that laboratory testing identified as glass. Those findings concern the submitted imitation specimens and do not describe these genuine gems. A trade name or a visible color change alone is insufficient to identify an unknown stone; a gemological examination can establish its identity.
Read our separate Zultanite (Glass) testing entry.
Care
Protect diaspore from knocks, pressure on exposed edges and abrupt temperature changes. Store loose stones separately. As a conservative care approach for a brittle mineral with cleavage, clean gently with a soft cloth or brief mild soapy-water cleaning rather than ultrasonic or steam equipment.
References
- Handbook of Mineralogy · Diaspore
- GIA · Purplish Pink Diaspore Reportedly from Afghanistan
- GIA · The Color Origin of Gem Diaspore
