Palygorskite is a unique phyllosilicate mineral characterized by its distinctive leather-like or cork-like fibrous texture. Collectors often find it in layered, matted masses within sedimentary clay beds where it forms via chemical precipitation in saline environments.
Is this palygorskite?
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 palygorskite with a known reference. Palygorskite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: earthy to waxy.
- 4Match the color rangeCompare against the expected color range: white, gray, brownish white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: earthy, massive.
Often confused with
Palygorskite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside palygorskite
Minerals reported to co-occur with palygorskite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mg,Al)₂Si₄O₁₀(OH)·4H₂O
- Mohs hardness
- 2-2.5
- Density
- 2.1-2.2 g/cm³
- Colors
- Streak
- White
- Luster
- Earthy to waxy
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Earthy, massive
- Cleavage
- Good on {110}
- Rarity
- Common
- Uses
- Industrial, Collector, Drilling mud additive
- Host rock
- An alteration product of magnesium silicates in soils and sediments; in lacustrine marls, carbonate rocks, and mafic igneous rocks; in clay gouge associated with fault movement
Where rockhounds find palygorskite
Classic worldwide localities
- Attapulgus, Decatur Co., Georgia, USA
- Sapillo Creek, Grant Co., New Mexico, USA
- Pend Oreille mine, Metaline Falls, Stevens Co., Washington, USA
- New Melones Dam, Calaveras Co., California, USA
- Palygorskaya, near the Popovka River, Perm, Russia
- Warren quarry, Enderby, Leicestershire, England
Field-hunting tip
Where it forms: An alteration product of magnesium silicates in soils and sediments; in lacustrine marls, carbonate rocks, and mafic igneous rocks; in clay gouge associated with fault movement. If you start seeing calcite, dolomite, talc in float, you are in the right ground. Typical habit: earthy, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify palygorskite?+
Where is palygorskite found?+
What rocks look like palygorskite?+
What minerals are found with palygorskite?+
What kind of rock does palygorskite form in?+
What is palygorskite used for?+
Find palygorskite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
