Corrensite is a regular mixed-layer clay mineral composed of alternating chlorite and swelling trioctahedral smectite layers. It typically forms as an alteration product in volcanic or sedimentary rocks and is often identified via X-ray diffraction due to its subtle structural differences from standard chlorite.
Is this corrensite?
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 corrensite with a known reference. Corrensite sits at Mohs 2-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Corrensite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Corrensite typically shows a earthy luster.
- 4Match the color rangeCompare against the expected color range: green, yellow, white, gray, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy.
Often confused with
Corrensite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside corrensite
Minerals reported to co-occur with corrensite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mg,Fe)₉(Si,Al)₈O₂₀(OH)₁₀·nH₂O
- Mohs hardness
- 2-3
- Density
- 2.4-2.8 g/cm³
- Streak
- White
- Luster
- Earthy
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Platy
- Cleavage
- Perfect Basal
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Hydrothermal Alteration Zones and Sedimentary Deposits
- Typical price
- $10-50 per specimen
Where rockhounds find corrensite
Classic worldwide localities
- Germany
- USA
- France
- Russia
- Czech Republic
Field-hunting tip
Look in hydrothermal alteration zones and sedimentary deposits country, the host setting where corrensite typically forms. If you start seeing calcite, dolomite, quartz in float, you are in the right ground. Field specimens usually show a platy habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find corrensite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
