Age: 1760 million years (deposition of sediment) to 1575 million years (alteration), Proterozoic
Location: Wallaroo, Yorke Peninsula
Formation: The heat and fluids from granite intrusions formed this distinctive metamorphic rock. The colourful minerals include epidote, actinolite and diopside (green); feldspar and haematite (orange and red) and magnetite (black). Quartzdolomite veins include pyrite and copper-bearing chalcopyrite.
Significance: This spectacular ‘Harlequin Stone’ is a widely exported decorative stone. It also expresses the geological event that formed the giant Olympic Dam orebody and the historic Moonta and Wallaroo copper mines.
Donated by: The Government of South Australia