Petarasite is a rare zirconium silicate mineral known for forming sharp, vitreous, yellowish-brown crystals in alkaline environments. It is most famously found in the peralkaline pegmatites of Mont Saint-Hilaire, where it is highly sought after by mineral enthusiasts. Collectors typically look for its distinct monoclinic prismatic habit associated with other rare-earth and alkaline silicate minerals.
Is this petarasite?
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 petarasite with a known reference. Petarasite sits at Mohs 5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Petarasite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Petarasite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brown, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic to tabular crystals.
Often confused with
Petarasite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside petarasite
Minerals reported to co-occur with petarasite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₅Zr₂Si₆O₁₈(Cl,OH)·2H₂O
- Mohs hardness
- 5
- Density
- 2.95 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic to Tabular Crystals
- Cleavage
- Distinct On {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Rocks in Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find petarasite
Classic worldwide localities
- Mount Saint-Hilaire, Quebec, Canada
- Khibiny Massif, Kola Peninsula, Russia
Field-hunting tip
Look in alkaline igneous rocks in pegmatites country — that is the host setting where petarasite typically forms. If you start seeing aegirine, microcline, analcime in float, you are in the right ground. Field specimens usually show a prismatic to tabular crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find petarasite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
