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, 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.
