Crocoite

Crocoite from the Adelaide Mine, Dundas, Tasmania, Australia, measuring 124 × 93 × 48 mm and weighing 397 grams.

Crocoite is a lead chromate that forms in the oxidised zone of lead deposits where a chromium source, usually from nearby ultramafic rock, is also present, a combination rare enough that the Dundas mineral field is regarded internationally as the premier source of the species. The Adelaide Mine is one of the historic Dundas workings most closely associated with fine Crocoite, producing the bright orange-red, elongated prismatic crystals that have made Tasmanian material the benchmark against which Crocoite from every other locality worldwide is judged.

This piece comes from the David Vince Collection. Dundas Crocoite from a named historic working like the Adelaide Mine is about as significant a piece as Australian mineralogy offers, and a genuinely important specimen for any serious collection.