HOPEITE

    Class : Phosphates, arsenates, vanadates
    Subclass : Hydrated phosphates
    Crystal system : Orthorhombic
    Chemistry : Zn3(PO4)2 4H2O
    Rarity : Rare

Hopeite is a rare zinc phosphate, it is a secondary mineral present in the oxidation zone of zinc deposits, along with smithsonite, hemimorphite and parahopeite. It was named in honor of the Scottish chemist Thomas Charles Hope, Professor at the University of Edinburgh. Hopeite forms tabular or prismatic crystals frequently grouped in parallel aggregates, more rarely kidney-shaped masses. Colorless to grayish white, sometimes pale yellow, or red if colored by iron oxides, it has perfect cleavage which helps in its determination.

Main photo : Hopeite from Kabwe Mine, Zambia © Rock Currier

Hopeite from Kabwe Mine, Zambia © Rock Currier
Hopeite from Kabwe Mine, Zambia © Bruce Cairncross
Hopeite from Kabwe Mine, Zambia © Peter Haas
Hemimorphite pseudomorph after hopeite from Kabwe Mine, Zambia © Rob Lavinsky

Hopeite in the World

The only beautiful crystals known come from the Broken Hill mine (Zambia), not to be confused with the Broken Hill of Australia. These are milky white prismatic crystals up to 3.5 cm and millimeter crystals coated with goethite. Hopeite is also known in the superficial parts of the zinc mines of Altenberg (or Vieille-Montagne, in Belgium), Bad Ems (Germany) and especially Hudson Bay (British Columbia, Canada). It is known in the more surprising context of American pegmatites (Tip-Top in South Dakota and Palermo in New Hampshire).

Hopeite in France

Hopeite is not present in the French underground.

Twinning

No twin known for this mineral species, but can replaced hemimorphite with which it shares its deposits.

Fakes and treatments

No fakes recorded for this mineral species.


Hardness : 3.5
Density : 3 to 3.1
Fracture : Irregular
Streak : White

TP : Translucent to transparent
RI : 1.572 to 1.592
Birefringence : 0.018
Optical character : Biaxial -
Pleochroism : None
Fluorescence : None

Solubility : Hydrochloric acid

Magnetism : NoneRadioactivity : None