Krasnoshteinite is a rare aluminum hydroxide, typically colorless. It formed by diagenetic or post-diagenetic processes in halite-carnallite evaporitic rock. It was first described from the Romanovskiy area, Verkhnekamskoe deposit, Perm Krai, Northwest Urals, Russia.
Is this krasnoshteinite?
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 krasnoshteinite with a known reference. Krasnoshteinite 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: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, radial aggregates.
Often confused with
Krasnoshteinite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Alunite is the harder of the two (Mohs 3.5-4 vs. 2).
How to tell apart: Streak differs, so Krasnoshteinite leaves white, Jarosite leaves pale yellow; luster reads vitreous on Krasnoshteinite and subadamantine to vitreous, resinous on fractures on Jarosite.
Often found alongside krasnoshteinite
Minerals reported to co-occur with krasnoshteinite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al₈[B₂O₄(OH)₂](OH)₁₆Cl₄·7H₂O
- Mohs hardness
- 2
- Density
- 2.11 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular crystals, radial aggregates
- Cleavage
- Perfect on {010} and imperfect on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- hydrothermal alteration zones
Where rockhounds find krasnoshteinite
Classic worldwide localities
- Krasnoshteynskoe deposit, Russia
Field-hunting tip
Where it forms: hydrothermal alteration zones. If you start seeing alunite, kaolinite, quartz in float, you are in the right ground. Typical habit: tabular crystals, radial aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify krasnoshteinite?+
Where is krasnoshteinite found?+
What rocks look like krasnoshteinite?+
What minerals are found with krasnoshteinite?+
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Find krasnoshteinite on the map
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