Tschermigite is a rare ammonium aluminum sulfate that typically forms as a white efflorescent crust or small octahedral crystals near burning coal seams. It is highly soluble in water and must be kept in a cool, dry environment to prevent dehydration and breakdown of the specimen.
Is this tschermigite?
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 tschermigite with a known reference. Tschermigite sits at Mohs 1.5-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tschermigite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Tschermigite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: cubic. Typical habit: octahedral crystals, fibrous crusts, or efflorescent masses.
Often confused with
Tschermigite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside tschermigite
Minerals reported to co-occur with tschermigite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (NH₄)Al(SO₄)₂·12H₂O
- Mohs hardness
- 1.5-2
- Density
- 1.65 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Cubic
- Crystal habit
- Octahedral Crystals, Fibrous Crusts, Or Efflorescent Masses
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Associated with Burning Coal Seams and Carbonaceous Shales
- Typical price
- $20-100 per specimen depending on crystal size
Where rockhounds find tschermigite
1 mapped spotsClassic worldwide localities
- Tschermig, Czech Republic
- Baker County, Oregon, USA
- Hunan Province, China
- Kyzyl-Kum, Uzbekistan
Field-hunting tip
Look in associated with burning coal seams and carbonaceous shales country, the host setting where tschermigite typically forms. If you start seeing jarosite, gypsum, sulfur in float, you are in the right ground. Field specimens usually show a octahedral crystals, fibrous crusts, or efflorescent masses habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Wyoming. Start trip planning there.
Common questions
How do you identify tschermigite?+
Where is tschermigite found?+
Can I find tschermigite in the United States?+
How much is tschermigite worth?+
What rocks look like tschermigite?+
What minerals are found with tschermigite?+
What kind of rock does tschermigite form in?+
What is tschermigite used for?+
Find tschermigite on the map
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