Limonite is a mixture of hydrated iron oxide minerals, primarily goethite, and lacks a defined crystal structure. It is frequently identified by its characteristic yellowish-brown streak and typically forms in earthy, botryoidal, or massive crusts in the weathering zones of iron deposits.
Is this limonite?
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 with a known reference. Limonite 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 leaves a yellowish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Limonite typically shows a submetallic to earthy luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, reddish-brown, black.
- 5Look at form & habitCrystal system: amorphous. Typical habit: massive, botryoidal, stalactitic, earthy.
Often confused with
Limonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Limonite leaves yellowish-brown, Iron Ore leaves reddish-brown to black; luster reads submetallic to earthy on Limonite and metallic to submetallic on Iron Ore.
How to tell apart: Streak differs, so Limonite leaves yellowish-brown, Sphalerite leaves white to yellow-brown; luster reads submetallic to earthy on Limonite and resinous to submetallic on Sphalerite.
Often found alongside limonite
Minerals reported to co-occur with limonite. 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
- Streak
- Yellowish-brown
- Luster
- Submetallic to Earthy
- Transparency
- Opaque
- Crystal system
- Amorphous
- Crystal habit
- Massive, Botryoidal, Stalactitic, Earthy
- Cleavage
- None
- Rarity
- Common
- Uses
- Pigment, Iron Ore, Collector
- Host rock
- Oxidized Zones of Iron-bearing Mineral Deposits, Sedimentary Iron Formations
- Typical price
- $5-50 for hand-sized specimens
Where rockhounds find limonite
70 mapped spotsClassic worldwide localities
- France
- Germany
- United States
- Brazil
- Russia
U.S. states with limonite
Each link opens a state-specific list of mapped rockhounding spots that produce limonite.
Field-hunting tip
Look in oxidized zones of iron-bearing mineral deposits, sedimentary iron formations country, the host setting where limonite typically forms. If you start seeing goethite, hematite, quartz in float, you are in the right ground. Field specimens usually show a massive, botryoidal, stalactitic, earthy habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah, North Carolina, Iowa. Start trip planning there.
Common questions
How do you identify limonite?+
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Find limonite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
