Dresserite is a rare barium aluminum carbonate mineral most notably found in the unique geological environment of the Mont Saint-Hilaire alkaline complex. It typically forms delicate white, bladed, or radiating spherical clusters within vugs of igneous rock.
Is this dresserite?
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 dresserite with a known reference. Dresserite sits at Mohs 2.5-3, 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 to silky.
- 4Match the color rangeCompare against the expected color range: white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: bladed aggregates, radial clusters, spherical aggregates.
Often confused with
Dresserite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside dresserite
Minerals reported to co-occur with dresserite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ba₂Al₄(CO₃)₄(OH)₈·3H₂O
- Mohs hardness
- 2.5-3
- Density
- 2.96 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to silky
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Bladed aggregates, radial clusters, spherical aggregates
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In vugs in an alkalic sill in limestone
Where rockhounds find dresserite
Classic worldwide localities
- Francon quarry, Montreal Island, Montreal, Quebec, Canada
Field-hunting tip
Where it forms: In vugs in an alkalic sill in limestone. If you start seeing weloganite, dawsonite, quartz in float, you are in the right ground. Typical habit: bladed aggregates, radial clusters, spherical aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify dresserite?+
Where is dresserite found?+
What rocks look like dresserite?+
What minerals are found with dresserite?+
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Find dresserite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
