Mn2+7(AsO4)2(OH)8
Identified from a single burnt orange-red broken crystal partially enclosed in Mn-carbonate, associated with gatehouseite, hausmannite, calcite, barite, and possibly rhodochrosite. Two other single crystal fragments were subsequently found, likely from the same specimen.
Selected Australian Occurrences:
- Only recorded from Iron Monarch, South Australia.
A photograph of allactite appears in the Minerals of Iron Monarch book. Arsenate minerals are rare at this locality where phosphate species are abundant.
