Pb₄(SO₄)(CO₃)₂(OH)₂

This sample of leadhillite is displayed in the Smithsonian Museum of Natural History. Leadhillite is a mineral of lead with both sulfate and carbonate groups. It has the composition Pb₄(SO₄)(CO₃)₂(OH)₂. The sample at left is about 5 cm across and is from Campbell shaft, Bisbee, Arizona.