Weloganite is a highly sought-after rare carbonate mineral found primarily in the unique alkaline rocks of Mont Saint-Hilaire. Collectors prize its distinct pseudo-hexagonal bipyramidal crystal form and its diagnostic bright fluorescence under ultraviolet light.
Is this weloganite?
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 weloganite with a known reference. Weloganite sits at Mohs 3.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Weloganite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Weloganite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-white, colorless.
- 5Look at form & habitCrystal system: trigonal. Typical habit: short prismatic to pseudo-hexagonal bipyramidal crystals.
Often confused with
Weloganite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside weloganite
Minerals reported to co-occur with weloganite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Sr₃Na₂Zr(CO₃)₆·3H₂O
- Mohs hardness
- 3.5
- Density
- 3.23 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Short Prismatic to Pseudo-hexagonal Bipyramidal Crystals
- Cleavage
- Distinct On {10-10}
- Fluorescence
- Bright Yellow to White Under SW/LW UV
- Rarity
- Rare
- Uses
- Collector, Scientific Research
- Host rock
- Alkaline Igneous Intrusions
- Typical price
- $50-500 depending on crystal size and matrix quality
Where rockhounds find weloganite
Classic worldwide localities
- Mont Saint-Hilaire, Quebec, Canada
Field-hunting tip
Look in alkaline igneous intrusions country — that is the host setting where weloganite typically forms. If you start seeing dresserite, dawsonite, analcime in float, you are in the right ground. Field specimens usually show a short prismatic to pseudo-hexagonal bipyramidal crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find weloganite on the map
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