Mereiterite is a rare potassium iron sulfate typically found as an oxidation product of sulfide minerals in mine workings. It usually occurs as fragile, colorless to white prismatic crystals or as efflorescent crusts, requiring careful handling due to its solubility in water.
Is this mereiterite?
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 mereiterite with a known reference. Mereiterite 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 to greasy.
- 4Match the color rangeCompare against the expected color range: pale yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: crystalline.
Often confused with
Mereiterite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside mereiterite
Minerals reported to co-occur with mereiterite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂Fe²⁺(SO₄)₂·4H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.36 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to greasy
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Crystalline
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A rare secondary mineral imbedded in gypsum, formed by decomposition of sulfides in a hydrothermal Pb–Zn–Cu ore deposit
Where rockhounds find mereiterite
Classic worldwide localities
- Laurium, Greece
Field-hunting tip
Where it forms: A rare secondary mineral imbedded in gypsum, formed by decomposition of sulfides in a hydrothermal Pb–Zn–Cu ore deposit. If you start seeing gypsum, smithsonite, goethite in float, you are in the right ground. Typical habit: crystalline. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mereiterite?+
Where is mereiterite found?+
What rocks look like mereiterite?+
What minerals are found with mereiterite?+
What kind of rock does mereiterite form in?+
What is mereiterite used for?+
Find mereiterite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
