Hackmanite (tenebrescent sodalite) 7.6g fluorescent

A compact hackmanite specimen with broad, even hackmanite coverage: in white light a soft pink-mauve occupies most of the main face, with only a small section of grey-beige feldspar matrix visible at the lower right corner. The hackmanite distribution is relatively even across the surface, which is notable for a rough specimen of this size. After UV exposure the pink-mauve deepens to a saturated purple-violet across nearly the full face. Under longwave UV (365nm) the piece fluoresces brilliant yellow-orange with near-complete, evenly distributed coverage. Under midwave UV (310nm) the response is a uniform bright magenta-pink covering the entire face with little variation.

Tenebrescence is hackmanite's reversible photochromic response: the mineral reads white to pale grey in its unexposed state, shifts to pink or violet under UV light or sunlight, and bleaches back in ordinary light or darkness, repeating the cycle without limit. The broad and even hackmanite distribution across this specimen's face means the color change is visible over a large surface area with minimal matrix interruption; the 310nm response in particular demonstrates uniform coverage, with the entire face responding in the same color. From Badakhshan, Afghanistan.

• Stone type: Natural hackmanite (tenebrescent sodalite)
• Weight: 7.6g
• Size: 27x19x12mm
• Color: Pink mauve (white light); purple (after UV)
• Fluorescence (365nm): Strong orange
• Fluorescence (310nm): Bright magenta-pink
• Cut: Rough
• Clarity: Opaque
• Treatment: Untreated
• Origin: Afghanistan

Natural hackmanite, tenebrescent sodalite, Afghanistan, sold loose.