Hydrozincite is a secondary zinc mineral commonly found as earthy or botryoidal crusts in the oxidized zones of zinc deposits. It is most easily identified by its characteristic bright blue fluorescence under shortwave UV light, which helps distinguish it from similar-looking white carbonate minerals.
Is this hydrozincite?
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 hydrozincite with a known reference. Hydrozincite sits at Mohs 2-2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hydrozincite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Hydrozincite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: white, grayish-white, yellowish-white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: botryoidal, massive, crusty, earthy.
Often confused with
Hydrozincite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Smithsonite is the harder of the two (Mohs 4-4.5 vs. 2-2.5); luster reads dull on Hydrozincite and vitreous on Smithsonite.
How to tell apart: Luster reads dull on Hydrozincite and adamantine on Cerussite.
How to tell apart: Hemimorphite is the harder of the two (Mohs 4.5-5 vs. 2-2.5); luster reads dull on Hydrozincite and vitreous on Hemimorphite.
Often found alongside hydrozincite
Minerals reported to co-occur with hydrozincite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Zn₅(CO₃)₂(OH)₆
- Mohs hardness
- 2-2.5
- Density
- 3.9-4.0 g/cm³
- Streak
- White
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Botryoidal, Massive, Crusty, Earthy
- Cleavage
- Perfect
- Fluorescence
- Bright Blue to White Under SW/LW UV
- Rarity
- Common
- Uses
- Collector, Ore of Zinc
- Host rock
- Oxidized Zinc Ore Deposits
- Typical price
- $5-30 per specimen
Where rockhounds find hydrozincite
4 mapped spotsClassic worldwide localities
- Laurion, Greece
- Bleiberg, Austria
- Mapimi, Mexico
- Broken Hill, Australia
- Salmo, British Columbia
Field-hunting tip
Look in oxidized zinc ore deposits country — that is the host setting where hydrozincite typically forms. If you start seeing smithsonite, hemimorphite, sphalerite in float, you are in the right ground. Field specimens usually show a botryoidal, massive, crusty, earthy habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Nevada, New Mexico, North Carolina — start trip planning there.
Common questions
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Find hydrozincite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
