Clinochlore is a member of the chlorite group, commonly found in metamorphic rocks as green, platy, or micaceous aggregates. Collectors often prize the chromium-rich violet variety known as Kammererite. Its perfect cleavage and pearly luster on cleavage faces make it distinct from other mica-group minerals.
Is this clinochlore?
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 clinochlore with a known reference. Clinochlore sits at Mohs 2-2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: greenish white to white.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly, greasy, dull.
- 4Match the color rangeCompare against the expected color range: blackish green, bluish green, white, yellowish green, olive green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: granular, massive, pseudo hexagonal.
Often confused with
Clinochlore vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Clinochlore leaves greenish white to white, Muscovite leaves white; luster reads pearly, greasy, dull on Clinochlore and vitreous to pearly or silky on Muscovite.
How to tell apart: Streak differs, so Clinochlore leaves greenish white to white, Biotite leaves white; luster reads pearly, greasy, dull on Clinochlore and splendent to submetallic, vitreous, pearly on cleavage on Biotite.
How to tell apart: Clinochlore is noticeably harder (Mohs 2-2.5 vs. 1); streak differs, so Clinochlore leaves greenish white to white, Talc leaves white.
Often found alongside clinochlore
Minerals reported to co-occur with clinochlore. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₅Al(AlSi₃O₁₀)(OH)₈
- Mohs hardness
- 2-2.5
- Density
- 2.60-3.02 g/cm³
- Streak
- Greenish white to white
- Luster
- Pearly, greasy, dull
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Granular, massive, pseudo hexagonal
- Cleavage
- {001}, perfect
- Rarity
- Common
- Uses
- Collector, Scientific research
- Host rock
- A hydrothermal alteration product of amphiboles, pyroxenes, biotite
Where rockhounds find clinochlore
2 mapped spotsClassic worldwide localities
- Emery mine, Chester, Hampden Co., Massachusetts, USA
- Texas, Lancaster Co., and West Chester, Chester Co., Pennsylvania, USA
- Tilly Foster mine, Brewster, Putnam Co., New York, USA
- Zillertal, Tirol, Austria
- Pfitschtal, Trentino-Alto Adige, Italy
- Val Malenco, Lombardy, Italy
Field-hunting tip
Where it forms: A hydrothermal alteration product of amphiboles, pyroxenes, biotite. If you start seeing serpentine, calcite, dolomite in float, you are in the right ground. Typical habit: granular, massive, pseudo hexagonal. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Maine, New York. Start trip planning there.
Common questions
How do you identify clinochlore?+
Where is clinochlore found?+
Can I find clinochlore in the United States?+
What rocks look like clinochlore?+
What minerals are found with clinochlore?+
What kind of rock does clinochlore form in?+
What is clinochlore used for?+
Find clinochlore on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
