Rozenite is a secondary sulfate mineral that typically forms as a white, powdery efflorescence on decomposing iron-sulfide minerals. It is notoriously unstable in humid conditions, often dehydrating or rehydrating depending on environmental humidity, requiring sealed storage for collectors.
Is this rozenite?
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 rozenite with a known reference. Rozenite sits at Mohs 2-3, 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, greenish, greenish white, yellowish white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, crusty, or powdery efflorescences.
Often confused with
Rozenite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside rozenite
Minerals reported to co-occur with rozenite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeSO₄·4H₂O
- Mohs hardness
- 2-3
- Density
- 2.293 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, crusty, or powdery efflorescences
- Cleavage
- Poor
- Rarity
- Common
- Uses
- Collector, Scientific research
- Host rock
- An uncommon secondary mineral, formed at or below 21°C and under low humidity directly from copper-free melanterite, in turn an alteration product of pyrite or marcasite
Where rockhounds find rozenite
Classic worldwide localities
- Bisbee, Cochise Co., Arizona, USA
- Kalkar quarry, Santa Cruz, Santa Cruz Co., California, USA
- Goldstrike mine, Lynn district, Humboldt Co., Nevada, USA
- Mt. Ornak, Tatra Mountains, and in the Staszic pyrite mine, Rudki, Poland
- Voras Mountains, 17 km north-northwest of Ardéa, Greece
- Alšar (Allchar), near Rošden, Macedonia
Field-hunting tip
Where it forms: An uncommon secondary mineral, formed at or below 21°C and under low humidity directly from copper-free melanterite, in turn an alteration product of pyrite or marcasite. If you start seeing melanterite, epsomite, jarosite in float, you are in the right ground. Typical habit: massive, crusty, or powdery efflorescences. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify rozenite?+
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Find rozenite on the map
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