Hopeite
Current inventory:  0 gems
 

  
Hopeite is named in honor of Thomas Charles Hope (1766–1844), Professor of Chemistry, University of Edinburgh, Edinburgh, Scotland.

Discovered in 1822;   IMA status:  Valid (pre-IMA; Grandfathered)

Chemistry

Chemical Formula:

Zn₃(PO₄)₂•4(H₂O)

Hydrated Zinc Phosphate

Molecular Weight:

458.17 gm

Composition:

Zinc

42.82 %

Zn

53.29 %

ZnO

Phosphorus

13.52 %

P

30.98 %

P₂O₅

Hydrogen

1.76 %

H

15.73 %

H₂O

Oxygen

41.90 %

O

100.00 %

100.00 %

= TOTAL OXIDE

Classification

Mineral Classification:

Phosphates

Strunz 8th Ed. ID:

7/C.11-20

Nickel-Strunz 10th Ed. ID:

8.CA.30

8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H₂O
A : With small and large/medium cations

Related to:

Hopeite Group. Dimorph of Parahopeite.

Varieties:

None

Synonyms:

α-Hopeite, β-Hopeite, Hibbenite

Crystal Data

Crystallography:

Orthorhombic - Dipyramidal

Crystal Habit:

Crystals tabular {010} to prismatic [001], and occurring individually or as tufted or divergent aggregates and crusts. Face development is frequently irregular. The crystals may simulate disphenoidal or hemimorphic symmetry. Reniform masses; compact.

Twinning:

None observed

Physical Properties

Cleavage:

Perfect on {010}; good on {100}; poor on {001}

Fracture:

Irregular/Uneven

Tenacity:

Brittle

Moh's Hardness:

3.5

Density:

3.00 - 3.10 (g/cm³)

Luminescence:

None

Radioactivity:

Not Radioactive

Other:

Readily soluble in dilute HCl.

Optical Properties

Color:

Colorless, Grayish White, pale Yellow, Brownish Orange; Colorless in transmitted light.

Transparency:

Transparent to Translucent

Luster:

Vitreous, Pearly on {010} cleavages

Refractive Index:

1.572 - 1.592  Biaxial  ( - ); sections || {100} are optically sectorially zoned.

Birefringence:

0.018

Dispersion:

Perceptible; r < v

Pleochroism:

None

Occurances

Geological Setting:

A rare, late-stage mineral in some hydrothermal zinc deposits and complex granite pegmatites; incrusting bone breccia in a limestone cave.

Common Associations:

Tarbuttite, Hemimorphite, Spencerite, Smithsonite, Vanadinite (Kabwe, Zambia); Triphylite, Ferrisicklerite, Leucophosphite, Laueite, Robertsite, Hydroxylapatite, Sphalerite (Tip Top mine, South Dakota, USA).

Common Impurities:

None

Type Locality:

Vieille Montagne (Altenberg; Kelmisberg), Moresnet, Kelmis, Plombières-Vieille Montagne (Plombières-Altenberg) District, Verviers, Liège Province, Belgium

Year Discovered:

1822

View mineral photos:

Hopeite Mineral Photos and Locations

More Information

Mindat.org 
Webmineral.com

Hopeite is a rare zinc phosphate mineral that is rarely available as a faceted gem. The only locality for gemmy crystals is Kabwe (Broken Hill), Central Province, Zambia. Crystals from this location can be very well formed and attractive in shades of brownish orange to orange but are very small. Hopeite is dimorphous with the mineral parahopeite. The two have the exact same chemistry but different structures. Hopeite is orthorhombic and parahopeite is triclinic.

Hopeite can be found at Vieille Montagne (Altenberg), Moresnet district, Belgium. In Germany, at Bad Ems, Rhineland-Palatinate; from Hagendorf, Bavaria; and at Oberschulenberg, Harz Mountains. Relatively large crystals at Kabwe (Broken Hill), Zambia. From the Hudson Bay mine, about eight km southeast of Salmo, British Columbia, Canada. In the USA, at the Tip Top mine, 8.5 km southwest of Custer, Custer County, South Dakota; from the Palermo #1 mine, near North Groton, Grafton County, New Hampshire; and in the Iron Cap Pb–Zn mine, near Aravaipa, Graham County, Arizona.
 

  
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