Amesite is a relatively rare member of the chlorite group, typically occurring as small, pearly, pseudohexagonal plates. It is best identified by its association with altered ultramafic rocks and its distinct micaceous habit compared to more common chlorite species.
Is this amesite?
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 amesite with a known reference. Amesite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white with pale green tint.
- 3Read the lusterHold the specimen under a strong light. Luster: pearly to somewhat metallic on cleavage surfaces.
- 4Match the color rangeCompare against the expected color range: white, light green.
- 5Look at form & habitCrystal system: triclinic. Typical habit: foliated, micaceous, pseudo hexagonal.
Often confused with
Amesite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Amesite leaves white with pale green tint, Clinochlore leaves greenish white to white.
How to tell apart: Streak differs, so Amesite leaves white with pale green tint, Chamosite leaves green to gray.
How to tell apart: Luster reads pearly to somewhat metallic on cleavage surfaces on Amesite and waxy, pearly on cleavage surfaces on Brucite.
Often found alongside amesite
Minerals reported to co-occur with amesite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₂Al(SiAl)O₅(OH)₄
- Mohs hardness
- 2.5-3
- Density
- 2.78 g/cm³
- Colors
- Streak
- White with pale green tint
- Luster
- Pearly to somewhat metallic on cleavage surfaces
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Foliated, micaceous, pseudo hexagonal
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A product of low-grade metamorphism of Al, Mg-rich rocks
Where rockhounds find amesite
Classic worldwide localities
- Emery mine, Chester, Hampden Co., Massachusetts, USA
- Lake Asbestos mine, Black Lake, Quebec, Canada
- Dufek mafic massif, Pensacola Mountains, Antarctica
- Postmasburg manganese deposits, Cape Province, South Africa
- Saranovskoye chromite deposits, Northern Ural Mountains, Russia
- Hällefors, Sweden
Field-hunting tip
Where it forms: A product of low-grade metamorphism of Al, Mg-rich rocks. If you start seeing vesuvianite, chlorite, magnetite in float, you are in the right ground. Typical habit: foliated, micaceous, pseudo hexagonal. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify amesite?+
Where is amesite found?+
What rocks look like amesite?+
What minerals are found with amesite?+
What kind of rock does amesite form in?+
What is amesite used for?+
Find amesite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
