Hopeite and Hemimorphite Locality: Vieille Montagne (Altenberg; Kelmisberg) , Moresnet , Plombières-Vieille Montagne (Plombières-Altenberg) District, Liège Province, Belgium. Size: View of 3.6 cm. — Photo: Didier Descouens · CC BY-SA 3.0
Hopeite
A rare hydrated zinc phosphate forming vitreous white-to-yellow orthorhombic prisms — a collector's species.
Intro adapted from Wikipedia (CC BY-SA).
Hopeite is an IMA-recognized mineral species in the phosphate class, with the chemical formula Zn₃(PO₄)₂·4H₂O.
It crystallizes in the orthorhombic crystal system (space group Pbnm). It is a member of the Hopeite structural group.
Key properties: Mohs hardness 3.5; specific gravity 3.05–3.06; White streak; Vitreous, pearly on {010} cleavages luster; optically biaxial.
IMA symbol Hop, grandfathered status — known before the IMA’s founding, named in 1826.
A rare, late-stage mineral in some hydrothermal zinc deposits and complex granite pegmatites; incrusting bone breccia in a limestone cave.
It is found associated with Tarbuttite, hemimorphite, spencerite, smithsonite, vanadinite (Kabwe, Zambia); triphylite, ferrisicklerite, leucophosphite, laueite, robertsite.
The mineral was named to honor Thomas Charles Hope (1766–1844), Professor of Chemistry, University of Edinburgh, Edinburgh, Scotland.