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, 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
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
