Zincovoltaite is a rare secondary sulfate mineral typically found as small, dark octahedral crystals in the oxidized zones of pyrite-rich ore deposits. It is chemically similar to voltaite but features zinc as the dominant divalent cation, often forming as an efflorescence in mine tunnels. Collectors should store specimens in dry, sealed containers as the mineral is water-soluble and prone to dehydration.
Is this zincovoltaite?
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 zincovoltaite with a known reference. Zincovoltaite sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Zincovoltaite leaves a greenish gray streak.
- 3Read the lusterHold the specimen under a strong light. Zincovoltaite typically shows a resinous luster.
- 4Match the color rangeCompare against the expected color range: black, dark green, brownish black.
- 5Look at form & habitCrystal system: cubic. Typical habit: octahedral crystals.
Often confused with
Zincovoltaite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside zincovoltaite
Minerals reported to co-occur with zincovoltaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂Zn₅Fe³⁺₃Al(SO₄)₁₂(OH)₂·18H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.6-2.7 g/cm³
- Streak
- Greenish Gray
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Cubic
- Crystal habit
- Octahedral Crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Oxidized Zones of Sulfide Ore Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find zincovoltaite
Classic worldwide localities
- Hope Mine, New Mexico, USA
- United Verde Mine, Arizona, USA
- Kremnica, Slovakia
- Alum Cave, Tennessee, USA
Field-hunting tip
Look in oxidized zones of sulfide ore deposits country — that is the host setting where zincovoltaite typically forms. If you start seeing jarosite, melanterite, gypsum in float, you are in the right ground. Field specimens usually show a octahedral crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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How much is zincovoltaite worth?+
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Find zincovoltaite on the map
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