Hopeite

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Hopeite
Hopeite Vieille Montagne.jpg
Hopeite Belgium - Type locality
General
CategoryPhosphate minerals
Formula
(repeating unit)
Zn3(PO4)2·4H2O
Strunz classification8.CA.30
Crystal systemOrthorhombic
Crystal classDipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m)
Space groupPnma
Identification
Formula mass458.17 g/mol
ColorColorless, Gray white, Yellow, White, Light yellow
Crystal habitEncrustations - Forms crust-like aggregates on matrix. Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline). Reniform - "Kidney like" in shape (e.g.. hematite).
Cleavage[100] Perfect, [010] Good, [001] Poor
FractureUneven - Flat surfaces (not cleavage) fractured in an uneven pattern.
Mohs scale hardness3-3.5
LusterVitreous (Glassy)
Streakwhite
Specific gravity3
Optical propertiesBiaxial (-), a=1.572-1.574, b=1.582-1.591, g=1.59-1.592
Other characteristicsnon-radioactive, non-magnetic

Hopeite is a hydrated zinc phosphate with formula: Zn3(PO4)2·4H2O. It is a rare mineral used mainly as a collectors specimen.

Hopeite crystallizes in the orthorhombic system with prismatic, vitreous white to yellow crystals. It also forms druzy encrustations and reniform (kidney-shaped) masses. The related mineral parahopeite, which has the same composition but different crystal structure, is triclinic. The minerals are formed through oxidation of sphalerite by the presence of phosphate-rich solutions

It was first described in 1822 from Moresnet, Liège Province, Belgium and is named after Scottish chemist, Thomas Charles Hope (1766–1844) of the University of Edinburgh.

It has been found in Zambia associated with lazulite.

Hopetite is one of the 2 conversion minerals arising from the application of the rust converter 'Fertan'.[1]

References[edit]

Orange-brown hopeite prisms to 3 mm on a nearly solid matrix of glassy, pastel yellow-green parahopeite crystals. Locality: Kabwe Mine (Broken Hill Mine), Kabwe, Central Province, Zambia. Broken Hill is the type locality for parahopeite.