Ardealite

Ca₂(PO₃OH)(SO₄)·4H₂O 

Ardealite forms as white to pale yellow fine-grained powdery masses in caves. It forms through the reaction of bat guano and calcite.

Selected Australian Occurrences:

• Cliefden Caves, New South Wales.
• Jenolan Caves, New South Wales.
• Moorba Cave, Western Australia.