Hydrodresserite is an extremely rare barium aluminum carbonate mineral primarily known from the alkaline rocks of Mont Saint-Hilaire in Quebec. It typically forms delicate, radiating clusters of acicular needles and is prized by advanced micromount collectors due to its rarity and specific formation environment.
Is this hydrodresserite?
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 hydrodresserite with a known reference. Hydrodresserite sits at Mohs 3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Hydrodresserite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Hydrodresserite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular crystals, radiated aggregates.
Often confused with
Hydrodresserite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside hydrodresserite
Minerals reported to co-occur with hydrodresserite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BaAl₂(CO₃)₂(OH)₄·3H₂O
- Mohs hardness
- 3
- Density
- 2.12 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular Crystals, Radiated Aggregates
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Intrusions
- Typical price
- $50-300 per specimen
Where rockhounds find hydrodresserite
Classic worldwide localities
- Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Look in alkaline igneous intrusions country — that is the host setting where hydrodresserite typically forms. If you start seeing dresserite, weloganite, calcite in float, you are in the right ground. Field specimens usually show a acicular crystals, radiated aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify hydrodresserite?+
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What rocks look like hydrodresserite?+
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Find hydrodresserite on the map
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