Diaspore – Color Change Turkish Gem, Zultanite and Csarite
Diaspore occupies a rare and prestigious position in the collector gemstone world — a naturally untreated, single-source Turkish mineral that undergoes one of the most visually arresting color transformations of any gemstone known to the trade. From kiwi green in daylight to raspberry pink or champagne under incandescent light, the color change of fine Turkish diaspore is a natural optical phenomenon driven by the mineral's manganese content and the spectral sensitivity of the human eye to different light sources. First discovered in the Ural Mountains of Russia in 1801, it was the Ilbir Mountains of southwestern Turkey that would eventually establish diaspore as a serious collector and luxury jewelry gemstone. This guide covers diaspore's mineralogy, the science of its color change, Turkish sources, trade names, clarity, and value.
Explore our natural color-change diaspore collection with full origin documentation and treatment disclosure.
Mineral Composition and Physical Properties
Diaspore is an aluminum oxide hydroxide mineral with the chemical formula AlO(OH). It belongs to the orthorhombic crystal system and is the dimorph of boehmite — both minerals share identical chemical composition but different crystal structures. Diaspore forms typically as prismatic or tabular crystals in metamorphic limestones, chloritic schists, altered igneous rocks, and bauxite deposits. It was first described in 1801 by the chemist Martin Klaproth, who named it from the Greek word for "to scatter" — a reference to its decrepitation (scattering) behavior when heated.
Gem-quality diaspore measures 6.5 to 7 on the Mohs hardness scale, providing adequate durability for jewelry use. It has perfect cleavage in one direction, which requires protective settings for ring applications. The specific gravity ranges from 3.30 to 3.40. The refractive index is biaxial positive at 1.702–1.750. The gemological constants of Turkish diaspore are consistent: RI 1.702–1.750, SG 3.30–3.40, birefringence 0.048.
The Color Change Mechanism
The color change in Turkish diaspore is produced by manganese (Mn³⁺) impurities within the crystal lattice. Manganese in this oxidation state has a broad absorption band in the orange-yellow region of the visible spectrum. The human visual system interprets transmitted light differently depending on the spectral composition of the illuminating source. Under daylight or cool fluorescent light — which is rich in blue and green wavelengths — the stone appears kiwi green, sage green, or yellowish-green. Under warm incandescent light — rich in orange and red wavelengths — the same stone transmits predominantly pink and purple wavelengths, resulting in the raspberry pink, champagne, or lavender tones that define the incandescent appearance of the stone.
The strength of the color change depends on manganese concentration and the optical path length through the stone (related to cut and size). Larger, well-cut specimens typically display a more pronounced and vivid color shift than smaller or shallower cuts.
Turkish Origins — The Ilbir Mountains
The Ilbir Mountains of Muğla Province in southwestern Turkey represent the only commercially significant source of gem-quality color-change diaspore in the world. The deposit occurs in a bauxite-rich geological formation that crystallized under specific metamorphic conditions approximately 30 million years ago. Mining is conducted at high altitude in challenging terrain, contributing to limited supply and the stone's collector status.
Only approximately 2% of the diaspore rough extracted from this deposit meets gem-quality standards. The majority of material is opaque or too heavily included for faceting. This extraordinary selectivity means that fine faceted diaspore represents only a small fraction of what is actually mined — a ratio that underpins its genuine scarcity in the market.
Trade Names — Zultanite® and Csarite®
The trade name Zultanite® was registered in 2006 by Steven Kotlowski, who chose the name in honor of the Ottoman sultans of Turkey (originally considered "Sultanite," the final name adopted a Z to avoid conflict with an already-registered mineral name). Csarite® is an alternative trademark from the same Turkish source material. Both trade names are legally protected and can only be applied to diaspore from specific licensed operations within the Ilbir Mountains deposit. Material from the same deposit sold by unlicensed parties may be labeled simply as Turkish diaspore or color-change diaspore — it is mineralogically and optically identical. GemPiece uses the accurate mineral name diaspore for all material, with full origin documentation provided.
Clarity Characteristics
Turkish color-change diaspore is generally a relatively clean gemstone for its type. Most faceted specimens are eye-clean to very slightly included, with the most common inclusions being fingerprints and fluid inclusions. Eye-clean material is available and represents the highest value tier. Slightly included material remains highly desirable due to the color-change property and origin rarity. Diaspore does not typically show the heavy inclusion landscapes common to emerald or some tourmalines.
Treatment Status
Color-change diaspore from Turkey is naturally untreated. No heat treatment, irradiation, fracture filling, or coating is applied to the natural material. The color change is entirely natural, produced by trace manganese in the crystal structure and requiring no enhancement. This untreated status is consistent across the species and is an important attribute for the collector and luxury jewelry market.
Value Factors
The strength and vividness of the color change is the primary value driver — stones that show a clearly distinct shift from vivid green to vivid pink command the highest prices per carat. Size is the second major factor: larger diaspore showing strong color change is genuinely scarce, and prices increase significantly above 3 carats in fine quality. Eye-clean clarity and expert cut add further value. Origin documentation from the Turkish Ilbir Mountains deposit provides collector provenance.
Durability and Jewelry Use
Diaspore's hardness of 6.5 to 7 makes it suitable for all standard jewelry applications. Perfect cleavage in one direction means that bezel or half-bezel settings are preferred for ring use to protect against impact along the cleavage plane. For earrings and pendants, standard prong settings are appropriate. Diaspore is a practical everyday jewelry stone when properly set.
Care and Maintenance
Clean diaspore with warm water, mild soap, and a soft brush. Avoid ultrasonic cleaning for stones with existing fractures or inclusions, as vibration may worsen these. Steam cleaning is generally safe for eye-clean specimens. Avoid prolonged exposure to strong heat sources. Store separately from harder gemstones. Avoid contact with harsh chemicals.
Explore Related Color-Change Gemstones
Collectors of color-change gemstones may also be interested in color change sapphire (view collection), andalusite (view collection), and andesine (view collection).
