Tancaite-(Ce) is an extremely rare iron tungstate mineral characterized by its distinct yellowish, platy crystalline habit. It is primarily known from the Tanca-Valle locality in Sardinia, where it occurs within hydrothermal vein deposits associated with ferberite.
Is this tancaite-(ce)?
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 tancaite-(ce) with a known reference. Tancaite-(Ce) sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tancaite-(Ce) leaves a yellow streak.
- 3Read the lusterHold the specimen under a strong light. Tancaite-(Ce) typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, yellowish-orange.
- 5Look at form & habitCrystal system: trigonal. Typical habit: platy crystals.
Often confused with
Tancaite-(Ce) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Tancaite-(Ce) leaves yellow, Wolframite leaves dark brown to black; luster reads vitreous on Tancaite-(Ce) and submetallic to metallic on Wolframite.
How to tell apart: Streak differs — Tancaite-(Ce) leaves yellow, Scheelite leaves white.
Often found alongside tancaite-(ce)
Minerals reported to co-occur with tancaite-(ce). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- FeWO₄·Fe(OH)₂
- Mohs hardness
- 3-4
- Density
- 4.15 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Trigonal
- Crystal habit
- Platy Crystals
- Cleavage
- Perfect
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Veins
- Typical price
- $50-300 per specimen
Where rockhounds find tancaite-(ce)
Classic worldwide localities
- Tanca-Valle, Sardinia, Italy
Field-hunting tip
Look in hydrothermal veins country — that is the host setting where tancaite-(ce) typically forms. If you start seeing ferberite, quartz, muscovite in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tancaite-(ce)?+
Where is tancaite-(ce) found?+
How much is tancaite-(ce) worth?+
What rocks look like tancaite-(ce)?+
What minerals are found with tancaite-(ce)?+
What kind of rock does tancaite-(ce) form in?+
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Find tancaite-(ce) on the map
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