Tantalowodginite is a rare member of the wodginite group characterized by its high tantalum content. It is primarily found as accessory minerals in complex granitic pegmatites, often appearing as dark, submetallic grains or small crystals embedded in feldspar or quartz matrices.

Hardness
5.5
Mohs
Luster
Vitreous to sub-adamantine
Streak
Yellowish tan
Transparency
Translucent

Is this tantalowodginite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

  • 1
    Test the hardness
    Try to scratch tantalowodginite with a known reference. Tantalowodginite sits at Mohs 5.5, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: yellowish tan.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: vitreous to sub-adamantine.
  • 4
    Match the color range
    Compare against the expected color range: brown.
  • 5
    Look at form & habit
    Crystal system: monoclinic. Typical habit: granular to prismatic crystals.

Often confused with

Tantalowodginite vs. its common look-alikes, and how to tell them apart in the field.

Often found alongside tantalowodginite

Minerals reported to co-occur with tantalowodginite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula
Mn²⁺Ta₂Ta₂O₈
Mohs hardness
5.5
Density
7.61 g/cm³
Colors
Streak
Yellowish tan
Luster
Vitreous to sub-adamantine
Transparency
Translucent
Crystal system
Monoclinic
Crystal habit
Granular to prismatic crystals
Cleavage
Distinct on {100}
Rarity
Rare
Uses
Collector, Scientific research
Host rock
In the quartz-K-feldspar core of a complexly zoned pegmatite dike intruded into high-grade metasedimentary migmatites

Where rockhounds find tantalowodginite

Classic worldwide localities

  • Emmons pegmatite, Uncle Tom Mountain, near Greenwood, Oxford Co., Maine, USA

Field-hunting tip

Where it forms: In the quartz-K-feldspar core of a complexly zoned pegmatite dike intruded into high-grade metasedimentary migmatites. If you start seeing tantalite-, wodginite, columbite- in float, you are in the right ground. Typical habit: granular to prismatic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify tantalowodginite?+
Mohs hardness is 5.5. Luster: vitreous to sub-adamantine. The streak is yellowish tan. Common colors include brown.
Where is tantalowodginite found?+
Notable localities include Emmons pegmatite, Uncle Tom Mountain, near Greenwood, Oxford Co., Maine, USA.
What rocks look like tantalowodginite?+
Tantalowodginite is most often confused with Wodginite, Tantalite, Columbite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with tantalowodginite?+
Tantalowodginite commonly co-occurs with Tantalite-, Wodginite, Columbite-, Muscovite, Fluorapatite, Quartz. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does tantalowodginite form in?+
Where it forms: In the quartz-K-feldspar core of a complexly zoned pegmatite dike intruded into high-grade metasedimentary migmatites. Working float back to the host body is the standard way to chase a fresh occurrence.
What is tantalowodginite used for?+
Tantalowodginite is used in collector, scientific research.

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