Laurentianite is a rare pyroxene group mineral primarily found in highly alkaline igneous environments like the Mont Saint-Hilaire complex. Collectors typically identify it by its specific associations with rare-earth bearing minerals in intrusive pegmatites and miarolitic cavities.
Is this laurentianite?
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 laurentianite with a known reference. Laurentianite sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Laurentianite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Laurentianite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless, gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals.
Often confused with
Laurentianite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside laurentianite
Minerals reported to co-occur with laurentianite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na(Fe³⁺,Mn³⁺)Si₂O₆
- Mohs hardness
- 5-6
- Density
- 2.3-2.5 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Complexes
- Typical price
- $50-300 per specimen
Where rockhounds find laurentianite
Classic worldwide localities
- Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Look in alkaline igneous complexes country — that is the host setting where laurentianite typically forms. If you start seeing aegirine, microcline, sodalite in float, you are in the right ground. Field specimens usually show a tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find laurentianite on the map
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