Reaphookhillite
Reaphookhillite is an IMA-recognized mineral species in the phosphate class, with the chemical formula MgZn₂(PO₄)₂·4H₂O.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Parahopeite structural group.
Key properties: Mohs hardness 4; specific gravity 3.03; Vitreous luster; optically biaxial.
IMA symbol Rea, IMA status: approved, named in 2019.
Found in unmetamorphosed, poorly sorted, argillaceous siltstones with conglomerate lenses, by groundwater causing near-surface enrichment of manganese, iron, zinc, and phosphorus.
It is found associated with Scholzite, leucophosphite, chalcophanite. Distribution From Reaphook Hill, Martins Well, Flinders Ranges, South Australia, Australia.
The name is derived from the locality where the studied material was collected.