Quick Facts
Formation & Origin
Diaspore is an aluminum oxyhydroxide that forms during the metamorphism of aluminum-rich rocks, particularly bauxite (the ore of aluminum) and emery deposits. Most diaspore is opaque and unremarkable, but a unique deposit in Turkey's Ilbir Mountains produces transparent, gem-quality crystals.
The Turkish gem diaspore is remarkable for its alexandrite-like color change: champagne or kiwi green in daylight shifts to pinkish-red under incandescent light. This effect comes from trace amounts of manganese that absorb different wavelengths depending on the light source's spectral composition.
The gem material has been marketed under trade names including 'Zultanite' (trademarked by one mining company), 'Csarite' (another trade name), and simply 'color-change diaspore.' All refer to the same material from the same Turkish deposit. The mine is small and production is limited, making this genuinely rare gem material.
Identification Guide
Gem diaspore is identified by its color-change effect (green/champagne to pink/red), hardness 7, orthorhombic crystal system, and high specific gravity (3.30-3.50). The color change under different light sources is the most dramatic identifier.
Distinguish from alexandrite (much higher RI, different SG), color-change garnet (isometric), and color-change sapphire (trigonal, higher RI). Diaspore has a perfect cleavage in one direction, which can be visible in faceted stones.
Spotting Fakes
Synthetic color-change corundum (alexandrite simulant) is sometimes sold as diaspore/Zultanite. Genuine diaspore has specific RI (1.702-1.750) and SG (3.30-3.50) ranges that differ from corundum. Lab reports from GIA or similar labs can confirm identity. The color change in genuine diaspore is typically more subtle than in alexandrite, shifting between champagne/green and pink rather than dramatic green-to-red.
Cultural & Metaphysical Traditions
Presented as cultural traditions, not scientific evidence
Diaspore is a relatively recent addition to crystal healing traditions, having only entered the gem market in the 2000s. Practitioners associate its color-change ability with adaptability, seeing situations from multiple perspectives, and finding beauty in transitions. The Turkish origin adds associations with the crossroads between East and West.
Where It's Found
Only significant gem source, marketed as 'Zultanite' and 'Csarite'
Small crystals, collector specimens
Type locality, non-gem material
Price Guide
Good to Know
Scratch test: At hardness 7, Diaspore can scratch glass and steel. It's durable enough for any type of jewelry.
Sources: Found in 3 notable locations worldwide, from Turkey to United States.
Heft test: Diaspore has average mineral density (3.30-3.50). It feels about as heavy as you'd expect from a stone its size.
Related Minerals
More famous color-change gem, different mineral
Polymorph with same chemistry, different structure
Related aluminum hydroxide mineral