Tapiolite-(Mn) is a rare tantalum-bearing mineral that crystallizes in the tetragonal system, distinguishing it from its orthorhombic polymorphs like tantalite. Collectors should look for dark, blocky, or dipyramidal crystals typically found within highly fractionated rare-element granitic pegmatites. Due to its high density and submetallic luster, it is often identified by its characteristic heavy weight relative to size.
Is this tapiolite-(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 tapiolite-(mn) with a known reference. Tapiolite-(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. Tapiolite-(Mn) leaves a yellowish-brown streak.
- 3Read the lusterHold the specimen under a strong light. Tapiolite-(Mn) typically shows a submetallic luster.
- 4Match the color rangeCompare against the expected color range: black, reddish-brown, brown.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: prismatic to pyramidal crystals, often showing dipyramidal forms.
Often confused with
Tapiolite-(Mn) vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Tapiolite-(Mn) leaves yellowish-brown, Columbium Ore leaves dark red to black.
How to tell apart: Streak differs — Tapiolite-(Mn) leaves yellowish-brown, Tapiolite-(Fe) leaves black.
How to tell apart: Streak differs — Tapiolite-(Mn) leaves yellowish-brown, Tantalite leaves black to reddish-brown; luster reads submetallic on Tapiolite-(Mn) and submetallic to resinous on Tantalite.
Often found alongside tapiolite-(mn)
Minerals reported to co-occur with tapiolite-(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
- 7.5-7.9 g/cm³
- Colors
- Streak
- Yellowish-brown
- Luster
- Submetallic
- Transparency
- Opaque
- Crystal system
- Tetragonal
- Crystal habit
- Prismatic to Pyramidal Crystals, Often Showing Dipyramidal Forms
- Cleavage
- Distinct On {101}
- Rarity
- Rare
- Uses
- Collector, Ore of Tantalum
- Host rock
- Granite Pegmatites
- Typical price
- $50-500 thumbnail to small cabinet specimens
Where rockhounds find tapiolite-(mn)
Classic worldwide localities
- Finland
- Sweden
- Brazil
- Australia
Field-hunting tip
Look in granite pegmatites country — that is the host setting where tapiolite-(mn) typically forms. If you start seeing microcline, albite, quartz in float, you are in the right ground. Field specimens usually show a prismatic to pyramidal crystals, often showing dipyramidal forms habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tapiolite-(mn)?+
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How much is tapiolite-(mn) worth?+
What rocks look like tapiolite-(mn)?+
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Find tapiolite-(mn) on the map
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