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, 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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