Witzkeite is a very rare hydrated sodium magnesium sulfate fluoride mineral first identified in industrial chemical environments. It typically forms thin tabular crystals that are delicate and easily soluble in water, making it a challenging mineral for collectors to preserve. Its occurrence is largely associated with anthropogenic evaporite processes and rare geological potash formations.
Is this witzkeite?
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 witzkeite with a known reference. Witzkeite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Witzkeite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Witzkeite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals.
Often confused with
Witzkeite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside witzkeite
Minerals reported to co-occur with witzkeite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₄Mg(SO₄)₂F₂·2H₂O
- Mohs hardness
- 2
- Density
- 1.74 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Evaporite Deposits
- Typical price
- $50-200 for rare specimens
Where rockhounds find witzkeite
Classic worldwide localities
- Haldor Topsøe factory, Denmark
- Potash deposits, various global locations
Field-hunting tip
Look in evaporite deposits country — that is the host setting where witzkeite typically forms. If you start seeing halite, gypsum, thenardite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find witzkeite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
