Opal-CT (variety lussatite) after fossil (Helix ramondi)

Les Rois Mine, Mur-sur-Allier, Pont-du-Château, Clermont-Ferrand District, Puy-de-Dôme Department, Auvergne-Rhône-Alpes  France

Specimen size: 1.3 × 1.2 × 0.5 cm = 0.51” × 0.47” × 0.20”