Minohlite is a rare copper-zinc sulfate mineral that typically appears as bright blue to blue-green platy crusts or delicate aggregates. It forms in the oxidized zones of ore deposits, often associated with other secondary copper and zinc minerals. Collectors value it for its vibrant color and rarity, often found in small micro-specimens from its type locality in Japan.
Is this minohlite?
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 minohlite with a known reference. Minohlite sits at Mohs <2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: pale green.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly to vitreous.
- 4Match the color rangeCompare against the expected color range: bluish green.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: platy crystals, crusts, aggregates.
Often confused with
Minohlite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads pearly to vitreous on Minohlite and vitreous to subadamantine, pearly on {0001} on Chalcophyllite.
How to tell apart: Streak differs, so Minohlite leaves pale green, Aurichalcite leaves light blue; luster reads pearly to vitreous on Minohlite and silky to pearly on Aurichalcite.
How to tell apart: Serpierite is the harder of the two (Mohs 3.5-4 vs. <2); streak differs, so Minohlite leaves pale green, Serpierite leaves greenish white; luster reads pearly to vitreous on Minohlite and vitreous, pearly on cleavages on Serpierite.
Often found alongside minohlite
Minerals reported to co-occur with minohlite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Cu₄Zn(SO₄)(OH)₆·3H₂O
- Mohs hardness
- <2
- Density
- 3.39 g/cm³
- Colors
- Streak
- Pale green
- Luster
- Pearly to vitreous
- Transparency
- Transparent
- Crystal system
- Hexagonal
- Crystal habit
- Platy crystals, crusts, aggregates
- Cleavage
- Perfect on {0001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral in the oxidized zone of a Cu Zn sulfide deposit
Where rockhounds find minohlite
Classic worldwide localities
- Hirao mine, Minoh (Minoo) City, Osaka Prefecture, Japan
Field-hunting tip
Where it forms: A secondary mineral in the oxidized zone of a Cu Zn sulfide deposit. If you start seeing chamosite, muscovite, smithsonite in float, you are in the right ground. Typical habit: platy crystals, crusts, aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
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Find minohlite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
