Silinaite is a rare phyllosilicate mineral that typically forms as white, platy crystals in alkaline igneous complexes. It is most famously found in the miarolitic cavities of Mont Saint-Hilaire, where it occurs alongside a variety of exotic rare-earth minerals. Due to its softness and perfect cleavage, specimens should be handled with care to prevent damage.
Is this silinaite?
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 silinaite with a known reference. Silinaite sits at Mohs 2.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Silinaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Silinaite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals.
Often confused with
Silinaite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Steacyite is the harder of the two (Mohs 5 vs. 2.5); luster reads pearly on Silinaite and vitreous on Steacyite.
How to tell apart: Gonnardite is the harder of the two (Mohs 5 vs. 2.5); luster reads pearly on Silinaite and vitreous on Gonnardite.
Often found alongside silinaite
Minerals reported to co-occur with silinaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- NaLiSi₂O₅·2H₂O
- Mohs hardness
- 2.5
- Density
- 2.32 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Intrusions
- Typical price
- $50-300 per specimen
Where rockhounds find silinaite
Classic worldwide localities
- Poudrette Quarry, Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Look in alkaline igneous intrusions country — that is the host setting where silinaite typically forms. If you start seeing microcline, aegirine, analcime in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find silinaite on the map
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