Columbite-Tantalite is a solid solution series often referred to as coltan, valued primarily as the main ore for tantalum and niobium. Collectors typically look for its characteristic submetallic luster and dense, blocky, or tabular crystals found within complex granitic pegmatites.
Is this columbite-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 columbite-tantalite with a known reference. Columbite-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. Columbite-Tantalite leaves a black streak.
- 3Read the lusterHold the specimen under a strong light. Columbite-Tantalite typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: black, brownish-black, brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic crystals, tabular crystals, massive.
Often confused with
Columbite-Tantalite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Columbite-Tantalite is noticeably harder (Mohs 6 vs. 4-4.5); streak differs — Columbite-Tantalite leaves black, Wolframite leaves dark brown to black; luster reads submetallic on Columbite-Tantalite and submetallic to metallic on Wolframite.
How to tell apart: Streak differs — Columbite-Tantalite leaves black, Cassiterite leaves white; luster reads submetallic on Columbite-Tantalite and adamantine on Cassiterite.
Often found alongside columbite-tantalite
Minerals reported to co-occur with columbite-tantalite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Fe,Mn)(Nb,Ta)₂O₆
- Mohs hardness
- 6
- Density
- 5.2-8.0 g/cm³
- Colors
- Streak
- Black
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic Crystals, Tabular Crystals, Massive
- Cleavage
- Distinct in One Direction
- Rarity
- Uncommon
- Uses
- Collector, Ore of Tantalum, Ore of Niobium
- Host rock
- Granite Pegmatites
- Typical price
- $15-100 thumbnail, $50-300 cabinet
Where rockhounds find columbite-tantalite
1 mapped spotsClassic worldwide localities
- Democratic Republic of the Congo
- Australia
- Brazil
- Canada
- Nigeria
Field-hunting tip
Look in granite pegmatites country — that is the host setting where columbite-tantalite typically forms. If you start seeing quartz, microcline, albite in float, you are in the right ground. Field specimens usually show a prismatic crystals, tabular crystals, massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in Wisconsin — start trip planning there.
Common questions
How do you identify columbite-tantalite?+
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Find columbite-tantalite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
