Townendite is an extremely rare cyclosilicate mineral primarily identified from the Poudrette quarry in Mont Saint-Hilaire, Quebec. It typically occurs as small, colorless grains within highly alkaline syenite pegmatites. Due to its extreme rarity and similarity to other zirconium silicates, identification usually requires specialized analytical techniques like microprobe analysis.
Is this townendite?
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 townendite with a known reference. Townendite sits at Mohs 5.5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Townendite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Townendite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: anhedral to subhedral grains.
Often confused with
Townendite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside townendite
Minerals reported to co-occur with townendite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₄LiZr₂Si₆O₁₈
- Mohs hardness
- 5.5
- Density
- 2.84 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Anhedral to Subhedral Grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Syenite Pegmatite
- Typical price
- $50-500 depending on specimen size
Where rockhounds find townendite
Classic worldwide localities
- Poudrette quarry, Canada
Field-hunting tip
Look in syenite pegmatite country — that is the host setting where townendite typically forms. If you start seeing microcline, aegirine, arfvedsonite in float, you are in the right ground. Field specimens usually show a anhedral to subhedral grains habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find townendite on the map
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