Ore deposit type: Magmatic-hydrothermal, skarn type
Provenance: Tuscany (Italy)
Description: Massive marmatitic sphalerite (dark-gray crystals with submetallic luster) in hedenbergite gangue (olive-green to brown acicular crystals). In skarns, the Ca silicates, such as hedenbergite, form by reactions between magmatic-hydrothermal fluids and carbonate country rocks.