Kainite is a water-soluble evaporite mineral commonly found in massive, granular forms within marine salt deposits. Collectors primarily identify it by its salty taste, though it is hygroscopic and must be stored in a dry, sealed environment to prevent degradation.
Is this kainite?
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 kainite with a known reference. Kainite 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.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless, blue, violet, gray, gray blue.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: encrustations, massive.
Often confused with
Kainite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kainite
Minerals reported to co-occur with kainite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KMg(SO₄)Cl·2.75H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.15 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Encrustations, massive
- Cleavage
- On {001}, perfect
- Rarity
- Common
- Uses
- Collector, Fertilizer, Industrial
- Host rock
- A secondary mineral in marine potash deposits, formed due to metamorphism or resolution by ground waters; rarely a volcanic sublimate
Where rockhounds find kainite
2 mapped spotsClassic worldwide localities
- Carlsbad potash district, Eddy Co., New Mexico, USA
- Stassfurt, 34 km south of Magdeburg, Saxony-Anhalt, Germany
- Werra-Fulda district, Hesse and Thuringia, Germany
- Asse Mountain, near Wolfenbüttel, and at the Kaliwerk Hansa Empelde, near Hannover, Saxony, Germany
- Racalmuto, Realmonte, on Sicily, Italy
- Kalusz and Stebnyk areas, Carpathian Mountains, Ukraine
Field-hunting tip
Where it forms: A secondary mineral in marine potash deposits, formed due to metamorphism or resolution by ground waters; rarely a volcanic sublimate. If you start seeing sylvite, halite, carnallite in float, you are in the right ground. Typical habit: encrustations, massive. Train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Nevada, Utah. Start trip planning there.
Common questions
How do you identify kainite?+
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Find kainite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
