Yttrotungstite-(Y) is an extremely rare secondary tungsten mineral typically found as an alteration product of ferberite or scheelite in oxidized zones. It generally forms soft, platy, or earthy masses that display a distinct pearly luster on cleavage surfaces.
Is this yttrotungstite-(y)?
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 yttrotungstite-(y) with a known reference. Yttrotungstite-(Y) sits at Mohs 2.5-3 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Yttrotungstite-(Y) leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Yttrotungstite-(Y) typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: yellow, brownish-yellow, greenish-yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy, fibrous aggregates, massive.
Often confused with
Yttrotungstite-(Y) vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside yttrotungstite-(y)
Minerals reported to co-occur with yttrotungstite-(y). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Y(WO₃)(OH)₃
- Mohs hardness
- 2.5-3
- Density
- 5.5-5.6 g/cm³
- Streak
- Yellow
- Luster
- Pearly
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Platy, Fibrous Aggregates, Massive
- Cleavage
- Perfect On {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Weathered Granite Pegmatites and Hydrothermal Tin-tungsten Veins
- Typical price
- $50-300 per specimen
Where rockhounds find yttrotungstite-(y)
Classic worldwide localities
- Pulacayo, Bolivia
- Kinta Valley, Malaysia
- Kigali, Rwanda
Field-hunting tip
Look in weathered granite pegmatites and hydrothermal tin-tungsten veins country — that is the host setting where yttrotungstite-(y) typically forms. If you start seeing ferberite, scheelite, tungstite in float, you are in the right ground. Field specimens usually show a platy, fibrous aggregates, massive habit, so train your eye for that shape before scanning the outcrop.




