Stilpnomelane "Chalcodite"

This specimen features vugs lined with quartz crystals in a hematite matrix, mostly coated by finely crystalline material formerly known as “chalcodite,” an obsolete name for a ferric member of the stilpnomelane group. The mineral displays the brassy-green colour and metallic lustre typical of stilpnomelane.

The Sterling Iron Mine, located north of Antwerp, was a notable source of mineral specimens before closing in 1910. The mine is also historically significant as the first identified occurrence of millerite in the United States. This specimen, with its quartz and stilpnomelane combo, represents a rare example from this long-closed and historically important locality.