Tancoite is an exceptionally rare phosphate mineral discovered at the Tanco pegmatite mine. It typically forms as small, transparent to translucent, colorless or pale pink crystals within complex pegmatite zones.
Is this tancoite?
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 tancoite with a known reference. Tancoite sits at Mohs 4-5 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tancoite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Tancoite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, pale pink.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals, granular masses.
Often confused with
Tancoite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside tancoite
Minerals reported to co-occur with tancoite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂LiHAl(PO₄)₂OH
- Mohs hardness
- 4-5
- Density
- 3.56 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular Crystals, Granular Masses
- Cleavage
- Distinct On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
- Typical price
- $50-300 per specimen
Where rockhounds find tancoite
Classic worldwide localities
- Tanco Mine, Manitoba, Canada
Field-hunting tip
Look in granite pegmatites country — that is the host setting where tancoite typically forms. If you start seeing albite, lepidolite, quartz in float, you are in the right ground. Field specimens usually show a tabular crystals, granular masses habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find tancoite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
