Hackmanite (tenebrescent sodalite) 6.8g fluorescent

A flat, elongated hackmanite specimen where the white-light appearance is dominated by warm beige-tan matrix, with a diagonal zone of soft pale pink-rose running across the left-center portion. The hackmanite color in white light is a muted, washed-out blush rather than a saturated purple, indicating a lower activation state in its ambient resting condition. After UV exposure the hackmanite zone shifts considerably: the pale rose deepens to a clear purple-violet and spreads more broadly, giving the piece a much stronger visual presence than in daylight. Under longwave UV (365nm) the stone fluoresces brilliant orange-yellow across the full surface. Under midwave UV (310nm) the response is a vivid pink-red to magenta-red glow.

Tenebrescence is hackmanite's reversible color shift: white or pale grey in darkness, pink to violet after UV or sunlight, bleaching back in ordinary light without any permanent change to the mineral. This piece illustrates well how the ambient-light and tenebrescent states can differ substantially: what reads as a low-saturation, largely matrix-dominated specimen in white light transforms into a clearly purple stone after UV activation, while the fluorescence under both 365nm and 310nm is strong regardless of the ambient color. From Badakhshan, Afghanistan.

• Stone type: Natural hackmanite (tenebrescent sodalite)
• Weight: 6.8g
• Size: 28x24x15mm
• Color: Pale pink (white light); purple (after UV)
• Fluorescence (365nm): Strong orange
• Fluorescence (310nm): Pink-red
• Cut: Rough
• Clarity: Opaque
• Treatment: Untreated
• Origin: Afghanistan

Natural hackmanite, tenebrescent sodalite, Afghanistan, sold loose.