Dietrichite is a rare zinc-dominant sulfate mineral that typically forms as delicate, white, fibrous crusts or tufts in the oxidized zones of sulfide mines. Because it is highly soluble and easily dehydrated, collectors must store these specimens in a dry, sealed environment to prevent them from breaking down or losing their crystal habit.
Is this dietrichite?
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 dietrichite with a known reference. Dietrichite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: silky.
- 4Match the color rangeCompare against the expected color range: brownish yellow, gray white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous.
Often confused with
Dietrichite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads silky on Dietrichite and vitreous to silky on Alunogen.
How to tell apart: Luster reads silky on Dietrichite and vitreous on Pickeringite.
How to tell apart: Luster reads silky on Dietrichite and vitreous on Halotrichite.
Often found alongside dietrichite
Minerals reported to co-occur with dietrichite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- ZnAl₂(SO₄)₄·22H₂O
- Mohs hardness
- 2
- Density
- 1.8 g/cm³
- Streak
- White
- Luster
- Silky
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- As post-mining efflorescences in abandoned mine workings
Where rockhounds find dietrichite
Classic worldwide localities
- Baia Sprie (Felsőbánya), Romania
Field-hunting tip
Where it forms: As post-mining efflorescences in abandoned mine workings. If you start seeing pyrite, gypsum, melanterite in float, you are in the right ground. Typical habit: fibrous. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify dietrichite?+
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Find dietrichite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
