Marcasite epimorph Calcite

Rarity from Sauerland: Lustrous metallic marcasite grew on slim, double-terminated calcite scalenohedrons up to 1.6 cm, which later dissolved away and the marcasite remained as a shell, which is called incrustation pseudomorph or perimorphism. The backside presents a rich nest of shiny, neat, brilliant white barite xls. 

Size: 4.0 x 2.7 x 2.0 cm

Locality: Dreislar, Sauerland, North Rhine-Westphalia, Germany