Diaspore (Zultanite)

Gem-quality color-change diaspore is relatively rare, and larger stones above 5 carats with good clarity and strong color change are highly prized. Carat weight significantly amplifies value when combined with attractive color performance.

Value depends on both base color and quality of color change. Stones that display a vivid green to kiwi tone in daylight and a warm pinkish, champagne or cognac hue indoors are most desirable. Weak, muddy or minimal color change reduces value considerably.

High-end diaspore is expected to be eye-clean or nearly so, particularly because inclusions can interfere with color and brilliance. Minor inclusions may be accepted in larger stones, but obvious fractures or clouds significantly reduce desirability.

Cutting is crucial for showcasing pleochroism and color change. Skillful orientation and well-proportioned mixed cuts can highlight multiple colors as the stone moves. Poor cutting that results in windowing or uneven color face-up diminishes the stone's main selling point.

The primary modern source of gem-quality diaspore is a limited region in Turkey, with additional small occurrences elsewhere. Mining is relatively small-scale and tightly controlled, leading to constrained supplies of fine color-change material.

Demand is driven by the novelty of natural color change and strong branding efforts around trade names like Zultanite. Collectors and colored stone enthusiasts form the core customer base, supplemented by consumers seeking something distinctive for engagement or statement rings.

Increased marketing over the last decade has raised awareness of diaspore, leading to more consistent demand and firming prices for fine stones, particularly those with documented origin and brand provenance.