Tantalite-(Fe) is a heavy, dark-colored mineral occurring primarily in rare-element granitic pegmatites. Collectors look for its characteristic submetallic luster and distinct orthorhombic prismatic habits, often embedded within coarse-grained feldspar or quartz matrices.
Is this tantalite-(fe)?
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 tantalite-(fe) with a known reference. Tantalite-(Fe) sits at Mohs 6-6.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: black.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic to vitreous.
- 4Match the color rangeCompare against the expected color range: black, brownish black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular to prismatic crystals, often as granular or massive aggregates.
Often confused with
Tantalite-(Fe) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Tantalite-(Fe) leaves black, Columbite leaves blackish brown.
How to tell apart: Tantalite-(Fe) is noticeably harder (Mohs 6-6.5 vs. 4.5); streak differs, so Tantalite-(Fe) leaves black, Wolframite leaves reddish brown.
How to tell apart: Luster reads submetallic to vitreous on Tantalite-(Fe) and metallic to submetallic on Ilmenite.
All properties
- Chemical formula
- FeTa₂O₆
- Mohs hardness
- 6-6.5
- Density
- 6.65-7.95 g/cm³
- Colors
- Streak
- Black
- Luster
- Submetallic to vitreous
- Transparency
- Opaque, translucent in thin edges
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular to prismatic crystals, often as granular or massive aggregates
- Cleavage
- {100}, distinct; {010}, less distinct
- Rarity
- Uncommon
- Uses
- Ore of tantalum, Collector specimen
- Host rock
- As an accessory and primary constituent of granite pegmatites
Where rockhounds find tantalite-(fe)
Classic worldwide localities
- Upper Bear Gulch, Lawrence Co., South Dakota, USA
- Moss, Norway
- Spittal an der Drau, Austria
- Nyanga, Uganda
- Muhembe, Rwanda
- Yellowknife district, Northwest Territories, Canada
Field-hunting tip
Where it forms: As an accessory and primary constituent of granite pegmatites. If you start seeing tapiolite- in float, you are in the right ground. Typical habit: tabular to prismatic crystals, often as granular or massive aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tantalite-(fe)?+
Where is tantalite-(fe) found?+
What rocks look like tantalite-(fe)?+
What minerals are found with tantalite-(fe)?+
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Find tantalite-(fe) on the map
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