Lawrencite is a highly unstable, deliquescent mineral that primarily occurs as a weathering product on iron-nickel meteorites. Collectors often know it as the 'rust disease' that causes meteorites to spontaneously disintegrate by attracting atmospheric moisture and forming acidic solutions.
Is this lawrencite?
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 lawrencite with a known reference. Lawrencite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Lawrencite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Lawrencite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: green, brown, colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: crusts, granular, efflorescent.
Often confused with
Lawrencite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Akaganeite is the harder of the two (Mohs 3-4 vs. 2); streak differs — Lawrencite leaves white, Akaganeite leaves yellowish-brown; luster reads vitreous on Lawrencite and dull on Akaganeite.
How to tell apart: Iron Ore is the harder of the two (Mohs 5-6.5 vs. 2); streak differs — Lawrencite leaves white, Iron Ore leaves reddish-brown to black; luster reads vitreous on Lawrencite and metallic to submetallic on Iron Ore.
Often found alongside lawrencite
Minerals reported to co-occur with lawrencite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeCl₂
- Mohs hardness
- 2
- Density
- 2.5-2.6 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Crusts, Granular, Efflorescent
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Iron-nickel Meteorites
- Typical price
- $20-100 per specimen
Where rockhounds find lawrencite
Classic worldwide localities
- Atacama Desert, Chile
- Campo del Cielo, Argentina
- Various iron meteorite find sites
Field-hunting tip
Look in iron-nickel meteorites country — that is the host setting where lawrencite typically forms. If you start seeing goethite, kamacite, taenite in float, you are in the right ground. Field specimens usually show a crusts, granular, efflorescent habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find lawrencite on the map
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