A limonite cube is a classic mineral pseudomorph, in which limonite has replaced an original pyrite crystal while retaining its distinct cubic habit. It feels much lighter than the pyrite it replaced and shows a characteristic yellow-brown to earthy brown streak. Collectors seek it for its sharp geometry and the chemical alteration story behind it.
Is this limonite cube?
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 limonite cube with a known reference. Limonite Cube sits at Mohs 4-5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Limonite Cube leaves a yellow-brown streak.
- 3Read the lusterHold the specimen under a strong light. Limonite Cube typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: brown, yellow-brown, black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: pseudocubic.
Often confused with
Limonite Cube vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Limonite Cube leaves yellow-brown, Pyrite leaves greenish-black to brownish-black; luster reads submetallic on Limonite Cube and metallic on Pyrite.
How to tell apart: Streak differs, so Limonite Cube leaves yellow-brown, Iron Ore leaves reddish-brown to black; luster reads submetallic on Limonite Cube and metallic to submetallic on Iron Ore.
Often found alongside limonite cube
Minerals reported to co-occur with limonite cube. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeO(OH)·nH₂O
- Mohs hardness
- 4-5.5
- Density
- 2.7-4.3 g/cm³
- Colors
- Streak
- Yellow-brown
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Pseudocubic
- Cleavage
- None
- Rarity
- Common
- Uses
- Collector, Lapidary
- Host rock
- Sedimentary Iron Deposits
Where rockhounds find limonite cube
3 mapped spotsClassic worldwide localities
- Utah, USA
- Missouri, USA
- Germany
- Czech Republic
Field-hunting tip
Look in sedimentary iron deposits country, the host setting where limonite cube typically forms. If you start seeing goethite, quartz, hematite in float, you are in the right ground. Field specimens usually show a pseudocubic habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Montana, North Carolina, South Carolina. Start trip planning there.
More limonite cube photos
Common questions
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Find limonite cube on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
