Scorodite is a secondary mineral commonly found in the oxidation zones of arsenic-bearing ore deposits. Collectors prize its sharp, often bipyramidal green to blue crystals, though it is frequently found as earthy or botryoidal masses.
Is this scorodite?
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 scorodite with a known reference. Scorodite sits at Mohs 3.5-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: greenish white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to subadamantine, subresinous.
- 4Match the color rangeCompare against the expected color range: yellowish green, pale leek green, liver brown, blue green, black green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: earthy, fibrous, granular.
Often confused with
Scorodite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Scorodite is noticeably harder (Mohs 3.5-4 vs. 1.5-2); streak differs, so Scorodite leaves greenish white, Vivianite leaves white, altering to dark blue, brown.
How to tell apart: Streak differs, so Scorodite leaves greenish white, Mimetite leaves white; luster reads vitreous to subadamantine, subresinous on Scorodite and resinous to subadamantine on Mimetite.
How to tell apart: Scorodite is noticeably harder (Mohs 3.5-4 vs. 2.5); streak differs, so Scorodite leaves greenish white, Pharmacosiderite leaves yellowish green; luster reads vitreous to subadamantine, subresinous on Scorodite and adamantine to greasy on Pharmacosiderite.
Often found alongside scorodite
Minerals reported to co-occur with scorodite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe³⁺AsO₄·2H₂O
- Mohs hardness
- 3.5-4
- Density
- 3.27 g/cm³
- Colors
- Streak
- Greenish white
- Luster
- Vitreous to subadamantine, subresinous
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Earthy, fibrous, granular
- Cleavage
- {201}, imperfect; {001}, {100}, in traces
- Rarity
- Uncommon
- Uses
- Collector, Indicator mineral
- Host rock
- A secondary mineral formed by oxidation of As-bearing sulfides
Where rockhounds find scorodite
3 mapped spotsClassic worldwide localities
- Gold Hill, Tooele Co., and in the Tintic district, Juab Co., Utah, USA
- Majuba Hill mine, Antelope district, Pershing Co., Nevada, USA
- Schwarzenberg, Saxony, and in the Clara mine, near Oberwolfach, Black Forest, Germany
- Horní Slavkov (Schlaggenwald), Czech Republic
- Lölling, Carinthia, Austria
- Found at a number of places in Gwennap, Calstock, in Cornwall, England
Field-hunting tip
Where it forms: A secondary mineral formed by oxidation of As-bearing sulfides. If you start seeing pharmacosiderite, beudantite, carminite in float, you are in the right ground. Typical habit: earthy, fibrous, granular. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in New York, Utah, Washington. Start trip planning there.
Common questions
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Find scorodite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
