Hopeite is a rare hydrated zinc phosphate typically found in the oxidized zones of zinc-rich ore deposits. Collectors look for its characteristic orthorhombic prismatic crystals which often form elegant, colorless to pale yellow sprays on a matrix of smithsonite.
Is this hopeite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch hopeite with a known reference. Hopeite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hopeite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Hopeite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellowish, grayish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals, radial aggregates, crusts.
Often confused with
Hopeite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside hopeite
Minerals reported to co-occur with hopeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₃(PO₄)₂·4H₂O
- Mohs hardness
- 3.5
- Density
- 3.0-3.1 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals, Radial Aggregates, Crusts
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zinc Ore Deposits
- Typical price
- $20-150 thumbnail, $200+ cabinet
Where rockhounds find hopeite
Classic worldwide localities
- Broken Hill, Zambia
- Salmo, British Columbia, Canada
- Laurion, Greece
Field-hunting tip
Look in oxidized zinc ore deposits country — that is the host setting where hopeite typically forms. If you start seeing smithsonite, hemimorphite, tarbuttite in float, you are in the right ground. Field specimens usually show a prismatic crystals, radial aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find hopeite on the map
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