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, 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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