Natural Hackmanite (Tenebrescent Sodalite) 18.1g Fluorescent

A substantial hackmanite rough with a large rounded hackmanite mass occupying the central and right portion of the piece, showing a relatively deep violet-purple even in white light. The sandy-white and orange-buff feldspar matrix is visible on the left side and edges, providing a clear boundary against the hackmanite zone. After UV exposure the hackmanite deepens further to a richer, more saturated purple-violet, with the matrix picking up faint lavender tinting at the edges where trace hackmanite is present. Under longwave UV (365nm) the piece fluoresces intense orange-red across the hackmanite zone. Under midwave UV (310nm) the response shifts to a completely different color: a deep blue-violet at the hackmanite core transitioning to pink-magenta toward the outer zones.

Tenebrescence is hackmanite's defining optical property: a reversible photochromic shift from white or pale grey in its light-bleached state to pink or violet under UV or sunlight, bleaching back in ordinary visible light without any permanent change, while in darkness the color holds. The two separate UV responses in this specimen, strong orange at 365nm and blue-violet to pink at 310nm, are independent phenomena driven by different excitation wavelengths; together they represent the specimen's full fluorescence range across two UV sources. From Badakhshan, Afghanistan.

Natural hackmanite, tenebrescent sodalite, Afghanistan, sold loose.