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 5-6, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: trigonal. 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
- Na₈ZrSi₆O₁₈
- Mohs hardness
- 5-6
- Density
- 2.95 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Trigonal
- Crystal habit
- Anhedral to subhedral grains
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In lujavrite layers of nepheline syenite in a layered alkaline igneous intrusion
Where rockhounds find townendite
Classic worldwide localities
- Kvanefjeld prospect, 8 km east of Narsak, Ilímaussaq alkaline complex, Southern Greenland
Field-hunting tip
Where it forms: In lujavrite layers of nepheline syenite in a layered alkaline igneous intrusion. If you start seeing albite, microcline, arfvedsonite in float, you are in the right ground. Typical habit: anhedral to subhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
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Find townendite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
