Haineaultite is an extremely rare mineral discovered in the alkaline igneous rocks of Mont Saint-Hilaire. It typically forms delicate, needle-like acicular crystals or radial sprays in small vugs, often requiring a microscope for proper identification.
Is this haineaultite?
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 haineaultite with a known reference. Haineaultite 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. Haineaultite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Haineaultite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, pale yellow, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular or fibrous radial aggregates.
Often confused with
Haineaultite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside haineaultite
Minerals reported to co-occur with haineaultite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Na,Ca)₅(Ca,Mn)₂(Ti,Nb)₂(Si₄O₁₂)₂(OH,F)₄·5H₂O
- Mohs hardness
- 3
- Density
- 2.44 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular or Fibrous Radial Aggregates
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Nepheline Syenite Pegmatites
- Typical price
- $50-300 per micro-specimen
Where rockhounds find haineaultite
Classic worldwide localities
- Poudrette quarry, Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Look in nepheline syenite pegmatites country, the host setting where haineaultite typically forms. If you start seeing analcime, aegirine, microcline in float, you are in the right ground. Field specimens usually show a acicular or fibrous radial aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find haineaultite on the map
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