Doyleite is a rare polymorph of aluminum hydroxide often found in alkaline pegmatite environments. It typically occurs as small, colorless to white tabular crystals and is prized primarily by mineral collectors specializing in rare species from localities like Mont Saint-Hilaire.
Is this doyleite?
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 doyleite with a known reference. Doyleite 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 pearly if colorless; otherwise dull.
- 4Match the color rangeCompare against the expected color range: white, creamy white, bluish white.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Doyleite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside doyleite
Minerals reported to co-occur with doyleite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Al(OH)₃
- Mohs hardness
- 2.5-3
- Density
- 2.48 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous to pearly if colorless; otherwise dull
- Transparency
- Transparent to opaque
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals
- Cleavage
- {010}, perfect; {100}, fair
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage hydrothermal mineral lining vugs in veins in nepheline syenite associated with an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada)
Where rockhounds find doyleite
Classic worldwide localities
- Found at Mont Saint-Hilaire, in the Francon quarry, Montreal Island, Montreal, and near Saint-Amable, Quebec, Canada
Field-hunting tip
Where it forms: A late-stage hydrothermal mineral lining vugs in veins in nepheline syenite associated with an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada). If you start seeing calcite, albite, pyrite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify doyleite?+
Where is doyleite found?+
What rocks look like doyleite?+
What minerals are found with doyleite?+
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Find doyleite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
