Leonite is a rare potassium-magnesium sulfate that typically forms in marine evaporite beds. It is often found as clear to white tabular crystals or as massive, granular crusts that are highly soluble in water and should be kept in a dry, sealed environment to prevent dehydration.
Is this leonite?
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 leonite with a known reference. Leonite 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: waxy to vitreous.
- 4Match the color rangeCompare against the expected color range: colorless, light yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, massive, granular.
Often confused with
Leonite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside leonite
Minerals reported to co-occur with leonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂Mg(SO₄)₂·4H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.20 g/cm³
- Colors
- Streak
- White
- Luster
- Waxy to vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals, massive, granular
- Cleavage
- None
- Rarity
- Uncommon
- Uses
- Collector, Mineralogical study
- Host rock
- An uncommon secondary mineral of metamorphic origin in marine salt deposits; may occur in volcanic fumaroles
Where rockhounds find leonite
Classic worldwide localities
- Carlsbad potash district, Eddy Co., New Mexico, USA
- Stassfurt potash district, as at Westeregeln, Leopoldshall, Aschersleben, Vienenburg, Riedel-Hänigsen, Saxony-Anhalt, Germany
- Sigmundshall mine, Bokeloh bei Wunstorf, Lower Saxony, Germany
- Vesuvius, Campania, Italy
- Stebnyk, Poland
Field-hunting tip
Where it forms: An uncommon secondary mineral of metamorphic origin in marine salt deposits; may occur in volcanic fumaroles. If you start seeing kainite, polyhalite, halite in float, you are in the right ground. Typical habit: tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify leonite?+
Where is leonite found?+
What rocks look like leonite?+
What minerals are found with leonite?+
What kind of rock does leonite form in?+
What is leonite used for?+
Find leonite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
