Perraultite is a rare manganese-dominant silicate typically found in the miarolitic cavities of alkaline igneous rocks. It is most recognized for its distinct dark brown tabular crystal form and often occurs as an accessory mineral in complex pegmatites. Collectors primarily source this mineral from the famous Mont Saint-Hilaire locality in Canada.
Is this perraultite?
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 perraultite with a known reference. Perraultite 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. Perraultite leaves a yellowish brown streak.
- 3Read the lusterHold the specimen under a strong light. Perraultite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: dark brown, reddish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, radiating clusters.
Often confused with
Perraultite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Neptunite is the harder of the two (Mohs 5-6 vs. 3.5); streak differs — Perraultite leaves yellowish brown, Neptunite leaves brownish red.
How to tell apart: Streak differs — Perraultite leaves yellowish brown, Bornemanite leaves white.
Often found alongside perraultite
Minerals reported to co-occur with perraultite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KNa(Mn,Fe)₈Ti₂Si₈O₂₄(O,OH,F)₇
- Mohs hardness
- 3.5
- Density
- 3.36 g/cm³
- Colors
- Streak
- Yellowish Brown
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Radiating Clusters
- Cleavage
- Good On {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Alkaline Igneous Complexes
- Typical price
- $50-300 per specimen depending on size and quality
Where rockhounds find perraultite
Classic worldwide localities
- Mont Saint-Hilaire, Quebec, Canada
- Khibiny Massif, Kola Peninsula, Russia
Field-hunting tip
Look in alkaline igneous complexes country — that is the host setting where perraultite typically forms. If you start seeing aegirine, microcline, analcime in float, you are in the right ground. Field specimens usually show a tabular crystals, radiating clusters habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find perraultite on the map
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