Tantalite is the primary ore for tantalum, a critical metal used in high-capacity capacitors. It is identified by its heavy weight and submetallic luster, typically found as dark, tabular crystals within granitic pegmatites.
Is this tantalite?
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 with a known reference. Tantalite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tantalite leaves a black to reddish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Tantalite typically shows a submetallic to resinous luster.
- 4Match the color rangeCompare against the expected color range: black, brownish-black, reddish-brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular, prismatic, or blocky crystals often with striations.
Often confused with
Tantalite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Tantalite leaves black to reddish-brown, Columbium Ore leaves dark red to black; luster reads submetallic to resinous on Tantalite and submetallic on Columbium Ore.
How to tell apart: Tantalite is noticeably harder (Mohs 6 vs. 4-4.5); streak differs — Tantalite leaves black to reddish-brown, Wolframite leaves dark brown to black; luster reads submetallic to resinous on Tantalite and submetallic to metallic on Wolframite.
How to tell apart: Streak differs — Tantalite leaves black to reddish-brown, Cassiterite leaves white; luster reads submetallic to resinous on Tantalite and adamantine on Cassiterite.
Often found alongside tantalite
Minerals reported to co-occur with tantalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Fe,Mn)Ta₂O₆
- Mohs hardness
- 6
- Density
- 6.0-8.0 g/cm³
- Streak
- Black to Reddish-brown
- Luster
- Submetallic to Resinous
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular, Prismatic, Or Blocky Crystals Often with Striations
- Cleavage
- Distinct in One Direction
- Rarity
- Uncommon
- Uses
- Collector, Industrial
- Host rock
- Granite Pegmatites
- Typical price
- $20-150 for thumbnail to cabinet size specimens
Where rockhounds find tantalite
1 mapped spotsClassic worldwide localities
- Brazil
- Australia
- Canada
- Democratic Republic of the Congo
- Nigeria
Field-hunting tip
Look in granite pegmatites country — that is the host setting where tantalite typically forms. If you start seeing microcline, albite, muscovite in float, you are in the right ground. Field specimens usually show a tabular, prismatic, or blocky crystals often with striations habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Alabama — start trip planning there.
Common questions
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Find tantalite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
