Dawsonite typically forms as delicate, radiating tufts or blades of white acicular crystals lining vugs in igneous or sedimentary rocks. It is most famous for its occurrences in the limestone quarries of the Montreal area, where it is found associated with various other carbonates and zeolites.
Is this dawsonite?
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 dawsonite with a known reference. Dawsonite 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. Dawsonite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Dawsonite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, gray.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: bladed crystals, acicular sprays, radiating tufts.
Often confused with
Dawsonite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside dawsonite
Minerals reported to co-occur with dawsonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaAl(CO₃)(OH)₂
- Mohs hardness
- 3
- Density
- 2.44 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Bladed Crystals, Acicular Sprays, Radiating Tufts
- Cleavage
- Perfect in One Direction
- Rarity
- Uncommon
- Uses
- Collector, Scientific Research
- Host rock
- Alkaline Igneous Rocks, Carbonatites, And Oil Shales
- Typical price
- $10-60 for thumbnail specimens
Where rockhounds find dawsonite
1 mapped spotsClassic worldwide localities
- Montreal, Quebec, Canada
- Tuscany, Italy
- Green River Formation, USA
Field-hunting tip
Look in alkaline igneous rocks, carbonatites, and oil shales country — that is the host setting where dawsonite typically forms. If you start seeing calcite, quartz, dolomite in float, you are in the right ground. Field specimens usually show a bladed crystals, acicular sprays, radiating tufts habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Utah — start trip planning there.
Common questions
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Find dawsonite on the map
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