Römerite is a secondary sulfate mineral typically found as a post-mining efflorescence in oxidized sulfide deposits. Collectors should look for its distinctive brownish-red tabular crystals in arid environments where iron-rich rocks have been exposed to atmospheric weathering.
Is this römerite?
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 römerite with a known reference. Römerite sits at Mohs 3-3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: oily, resinous, vitreous.
- 4Match the color rangeCompare against the expected color range: yellow, brown, violet brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: massive.
Often confused with
Römerite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Römerite leaves yellow, Copiapite leaves pale yellow; luster reads oily, resinous, vitreous on Römerite and pearly on {010} on Copiapite.
How to tell apart: Streak differs, so Römerite leaves yellow, Coquimbite leaves white; luster reads oily, resinous, vitreous on Römerite and vitreous on Coquimbite.
How to tell apart: Streak differs, so Römerite leaves yellow, Jarosite leaves pale yellow; luster reads oily, resinous, vitreous on Römerite and subadamantine to vitreous, resinous on fractures on Jarosite.
Often found alongside römerite
Minerals reported to co-occur with römerite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe²⁺Fe³⁺₂(SO₄)₄·14H₂O
- Mohs hardness
- 3-3.5
- Density
- 2.174 g/cm³
- Streak
- Yellow
- Luster
- Oily, resinous, vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Massive
- Cleavage
- On {010}, perfect; {001}, less perfect
- Rarity
- Uncommon
- Uses
- Collector
- Host rock
- As an early alteration product of oxidizing pyrite or pyrrhotite; uncommonly a volcanic sublimate
Where rockhounds find römerite
Classic worldwide localities
- United Verde mine, Jerome, Yavapai Co., and the Copper Queen mine, Bisbee, Cochise Co., Arizona, USA
- Island Mountain mine, Trinity Co., and the Leviathan mine, Alpine Co., California, USA
- Dexter mine group, Calf Mesa, San Rafael district, Emery Co., Utah, USA
- Rammelsberg mine, near Goslar, Harz Mountains, Germany
- Pfaffenreuth, near Waldsassen, Bavaria, Germany
- Tmavýdůl coal mine, near Rtyně, and from Příbram, Czech Republic
Field-hunting tip
Where it forms: As an early alteration product of oxidizing pyrite or pyrrhotite; uncommonly a volcanic sublimate. If you start seeing copiapite, melanterite, voltaite in float, you are in the right ground. Typical habit: massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify römerite?+
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What rocks look like römerite?+
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Find römerite on the map
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