Carminite is a rare and striking lead-iron arsenate mineral primarily found in the oxidized zones of arsenic-rich hydrothermal ore deposits. Collectors prize its vibrant carmine-red, needle-like or bladed crystals that typically form beautiful radiating sprays or crusts. It is most frequently associated with other secondary arsenic minerals like mimetite and scorodite.
Is this carminite?
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 carminite with a known reference. Carminite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: reddish yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly on cleavages.
- 4Match the color rangeCompare against the expected color range: carmine red, reddish brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular, lath.
Often confused with
Carminite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Carminite is noticeably harder (Mohs 3.5 vs. 1.5-2); streak differs, so Carminite leaves reddish yellow, Ludlockite leaves pale brown; luster reads vitreous, pearly on cleavages on Carminite and subadamantine on Ludlockite.
How to tell apart: Streak differs, so Carminite leaves reddish yellow, Mimetite leaves white; luster reads vitreous, pearly on cleavages on Carminite and resinous to subadamantine on Mimetite.
How to tell apart: Streak differs, so Carminite leaves reddish yellow, Vanadinite leaves white to pale red or pale yellow; luster reads vitreous, pearly on cleavages on Carminite and subresinous to subadamantine on Vanadinite.
Often found alongside carminite
Minerals reported to co-occur with carminite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- PbFe²⁺₂ (AsO₄)₂ (OH)₂
- Mohs hardness
- 3.5
- Density
- 5.03-5.18 g/cm³
- Colors
- Streak
- Reddish yellow
- Luster
- Vitreous, pearly on cleavages
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular, lath
- Cleavage
- On {110}, distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An uncommon alteration product of arsenopyrite in some oxidized lead-bearing mineral deposits
Where rockhounds find carminite
Classic worldwide localities
- Eureka, Ruby Hill district, Eureka Co., and in the Killie mine, Spruce Mountain district, Elko Co., Nevada, USA
- Centennial Eureka mine, Tintic district, Juab Co., and at the Gold Hill mine, Tooele Co., Utah, USA
- Louise iron mine, near Horhausen, and in the Schöne Aussicht mine, near Dernbach, Westerwald, Germany
- Merkur mine, Ems, Rhineland-Palatinate, Germany
- Caldbeck Fells, and in the Wanthwaite mine, St. John’s in the Vale, Cumbria, England
- Hingston Downs Consols mine, Calstock, England
Field-hunting tip
Where it forms: An uncommon alteration product of arsenopyrite in some oxidized lead-bearing mineral deposits. If you start seeing beudantite, scorodite, dussertite in float, you are in the right ground. Typical habit: acicular, lath. Train your eye for that shape before scanning the outcrop.
Common questions
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Find carminite on the map
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