Bianchite is a rare secondary zinc sulfate mineral that typically forms as white, powdery efflorescences or crusts in the oxidized zones of mine workings. Collectors often find it associated with other sulfate minerals in historical zinc mines, though it is highly soluble and requires careful storage away from humidity.
Is this bianchite?
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 bianchite with a known reference. Bianchite sits at Mohs ~2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: white, colorless, yellow, yellowish white, light blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crusts, efflorescences, granular aggregates.
Often confused with
Bianchite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside bianchite
Minerals reported to co-occur with bianchite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- ZnSO₄·6H₂O
- Mohs hardness
- ~2.5
- Density
- 2.03-2.07 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Crusts, efflorescences, granular aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A post-mine mineral, typically in efflorescences on mine walls, an alteration product of oxidizing sulfides
Where rockhounds find bianchite
Classic worldwide localities
- Bisbee, Cochise Co., Arizona, USA
- Silver Plume district, Clear Creek Co., Colorado, USA
- Sterling Hill, Sussex Co., New Jersey, USA
- Ueberroth zinc mine, Friedensville, Lehigh Co., Pennsylvania, USA
- Cave del Predil, Raibl mine, south of Tarvisio, Friuli-Venezia Giulia, Italy
- Bleiberg, Carinthia, Austria
Field-hunting tip
Where it forms: A post-mine mineral, typically in efflorescences on mine walls, an alteration product of oxidizing sulfides. If you start seeing goslarite, melanterite, hydrozincite in float, you are in the right ground. Typical habit: crusts, efflorescences, granular aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bianchite?+
Where is bianchite found?+
What rocks look like bianchite?+
What minerals are found with bianchite?+
What kind of rock does bianchite form in?+
What is bianchite used for?+
Find bianchite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
