Tantalite-(Mn) is a heavy, dark-colored mineral typically found as well-formed prismatic crystals in complex granite pegmatites. It is the primary ore for tantalum and is highly valued by collectors for its sharp, geometric crystal shapes and high density.
Is this tantalite-(mn)?
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-(mn) with a known reference. Tantalite-(Mn) 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: red, scarlet to black.
- 3Read the lusterHold the specimen under a strong light. Luster: submetallic to vitreous.
- 4Match the color rangeCompare against the expected color range: black, brown.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: crystalline, disseminated, massive.
Often confused with
Tantalite-(Mn) vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Tantalite-(Mn) leaves red, scarlet to black, Columbite-(Fe) leaves blackish brown.
How to tell apart: Tantalite-(Mn) is noticeably harder (Mohs 6-6.5 vs. 4.5); streak differs, so Tantalite-(Mn) leaves red, scarlet to black, Wolframite leaves reddish brown.
Often found alongside tantalite-(mn)
Minerals reported to co-occur with tantalite-(mn). Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MnTa₂O₆
- Mohs hardness
- 6-6.5
- Density
- 6.65-8.00 g/cm³
- Streak
- Red, scarlet to black
- Luster
- Submetallic to vitreous
- Transparency
- Opaque, transparent in thin edges
- Crystal system
- Orthorhombic
- Crystal habit
- Crystalline, disseminated, massive
- Cleavage
- {100}, distinct; {010}, less distinct
- Rarity
- Uncommon
- Uses
- Ore of tantalum, Collector specimen
- Host rock
- An accessory and primary constituent of granite pegmatites; detrital in placers
Where rockhounds find tantalite-(mn)
Classic worldwide localities
- Amelia, Amelia Co., Virginia, USA
- Pala, San Diego Co., California, USA
- Found on the Island of Utö, Sweden
- Glenbuchat, Aberdeenshire, Scotland
- Facciatoia, Elba, Italy
- Zambesia, Tete, and Alto Ligonha districts, Mozambique
Field-hunting tip
Where it forms: An accessory and primary constituent of granite pegmatites; detrital in placers. If you start seeing microcline, beryl, lepidolite in float, you are in the right ground. Typical habit: crystalline, disseminated, massive. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tantalite-(mn)?+
Where is tantalite-(mn) found?+
Is tantalite-(mn) safe to handle?+
What rocks look like tantalite-(mn)?+
What minerals are found with tantalite-(mn)?+
What kind of rock does tantalite-(mn) form in?+
What is tantalite-(mn) used for?+
Find tantalite-(mn) on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
