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.

Hardness

Mohs

Luster

Vitreous on crystal surfaces, pitchy to resinous

Streak

Grayish green

Transparency

Transparent to translucent

mineralrareVoltaite Group family

Zincovoltaite

Hardness: ~3
Luster: Vitreous on crystal surfaces, pitchy to resinous
Streak: Grayish green
Transparency: Transparent to translucent

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Is this zincovoltaite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch zincovoltaite with a known reference. Zincovoltaite sits at Mohs ~3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: grayish green.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous on crystal surfaces, pitchy to resinous.
4
Match the color range
Compare against the expected color range: black, green, greenish black.
5
Look at form & habit
Crystal system: cubic. Typical habit: octahedral crystals.

Often confused with

Zincovoltaite vs. its common look-alikes, and how to tell them apart in the field.

mineral

Voltaite

Mohs 3

How to tell apart: Luster reads vitreous on crystal surfaces, pitchy to resinous on Zincovoltaite and resinous on Voltaite.

How to tell apart: Streak differs, so Zincovoltaite leaves grayish green, Coquimbite leaves white.

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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: K₂Zn₅Fe₃Al(SO₄)₁₂·18H₂O
Mohs hardness: ~3
Density: 2.765 g/cm³
Colors: Black Green Greenish black
Streak: Grayish green
Luster: Vitreous on crystal surfaces, pitchy to resinous
Transparency: Transparent to translucent
Crystal system: Cubic
Crystal habit: Octahedral crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In the oxidation zone of a Zn–Pb–Fe sulfide deposit, formed in an arid climate

Where rockhounds find zincovoltaite

Classic worldwide localities

Xitieshan Pb–Zn mine, south of Mt. Qilianshan, Chaidamu, Qinghai Province, China

Field-hunting tip

Where it forms: In the oxidation zone of a Zn–Pb–Fe sulfide deposit, formed in an arid climate. If you start seeing römerite, melanterite, gypsum in float, you are in the right ground. Typical habit: octahedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify zincovoltaite?+

Mohs hardness is ~3. Luster: vitreous on crystal surfaces, pitchy to resinous. The streak is grayish green. Common colors include black, green, greenish black.

Where is zincovoltaite found?+

Notable localities include Xitieshan Pb–Zn mine, south of Mt. Qilianshan, Chaidamu, Qinghai Province, China.

What rocks look like zincovoltaite?+

Zincovoltaite is most often confused with Voltaite, Coquimbite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with zincovoltaite?+

Zincovoltaite commonly co-occurs with Römerite, Melanterite, Gypsum, Pyrite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does zincovoltaite form in?+

Where it forms: In the oxidation zone of a Zn–Pb–Fe sulfide deposit, formed in an arid climate. Working float back to the host body is the standard way to chase a fresh occurrence.

What is zincovoltaite used for?+

Zincovoltaite is used in collector.

Find zincovoltaite on the map

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