Geschieberite is a rare sulfate mineral that typically forms as efflorescent coatings in mines or arid evaporite environments. It is highly soluble in water and requires careful storage in dry conditions to prevent dehydration or breakdown.
Is this geschieberite?
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 geschieberite with a known reference. Geschieberite 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. Streak: greenish white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: bright green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: fibrous, efflorescent crusts, acicular.
Often confused with
Geschieberite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Geschieberite leaves greenish white, Picromerite leaves white.
How to tell apart: Streak differs, so Geschieberite leaves greenish white, Leonite leaves white; luster reads vitreous on Geschieberite and waxy to vitreous on Leonite.
Often found alongside geschieberite
Minerals reported to co-occur with geschieberite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- K₂(UO₂)(SO₄)₂(H₂O)₂
- Mohs hardness
- ~2
- Density
- 3.259 g/cm³
- Colors
- Streak
- Greenish white
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Fibrous, efflorescent crusts, acicular
- Cleavage
- Perfect on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As a weathering product from the post-mining alteration of uraninite and sulfides in a Ag-Bi-Co-Ni-U bearing hydrothermal vein deposit
Where rockhounds find geschieberite
Classic worldwide localities
- Geschieber vein, Svornost mine (5th level), Jáchymov (Joachimsthal), Western Bohemia, Czech Republic
Field-hunting tip
Where it forms: As a weathering product from the post-mining alteration of uraninite and sulfides in a Ag-Bi-Co-Ni-U bearing hydrothermal vein deposit. If you start seeing svornostite, adolfpateraite, gypsum in float, you are in the right ground. Typical habit: fibrous, efflorescent crusts, acicular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify geschieberite?+
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Is geschieberite safe to handle?+
What rocks look like geschieberite?+
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Find geschieberite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
