Ore deposit type: Hydrothermal in sedimentary environments
Provenance: Val Vedra Mine, Colonna di Ponente (Lombardy, N Italy)
Description: Bituminous argillite with sphalerite mineralization (in reddish subhedral nodules) associated with calcite (white, anhedral). The sphalerite deposition was syn-diagenetic, as evidenced by the growth of the big crystalline sphalerite nodules and consequent confinement of the clay matrix in the intranodular interstices.