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Vigezzite is a rare radioactive member of the aeschynite group typically found in alpine pegmatites. It usually presents as small, brownish-yellow prismatic crystals and is prized by micromount collectors for its rarity and distinct mineralogy.

Hardness
4.5-5
Mohs
Luster
Submetallic
Streak
White
Transparency
Transparent

Is this vigezzite?

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 vigezzite with a known reference. Vigezzite sits at Mohs 4.5-5, softer than the next harder reference, harder than the previous one.
  • 2
    Check the streak
    Drag the specimen across an unglazed porcelain plate. Streak: white.
  • 3
    Read the luster
    Hold the specimen under a strong light. Luster: submetallic.
  • 4
    Match the color range
    Compare against the expected color range: orange, bright yellow orange.
  • 5
    Look at form & habit
    Crystal system: orthorhombic. Typical habit: euhedral crystals, prismatic, striated.

Often found alongside vigezzite

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

All properties

Chemical formula
CaNb₂O₆
Mohs hardness
4.5-5
Density
5.54 g/cm³
Colors
OrangeBright yellow orange
Streak
White
Luster
Submetallic
Transparency
Transparent
Crystal system
Orthorhombic
Crystal habit
Euhedral crystals, prismatic, striated
Cleavage
{010}, distinct
Rarity
Rare
Uses
Collector
Host rock
In miarolitic cavities in an albitized pegmatite in amphibolite and biotite gneiss (Orcesco, Italy)

Where rockhounds find vigezzite

Classic worldwide localities

  • Orcesco, on Alpe Rosso, Val Vigezzo, Piedmont, Italy
  • Kovdor massif, Kola Peninsula, Russia

Field-hunting tip

Where it forms: In miarolitic cavities in an albitized pegmatite in amphibolite and biotite gneiss (Orcesco, Italy). If you start seeing pyrochlore, columbite, fersmite in float, you are in the right ground. Typical habit: euhedral crystals, prismatic, striated. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify vigezzite?+
Mohs hardness is 4.5-5. Luster: submetallic. The streak is white. Common colors include orange, bright yellow orange.
Where is vigezzite found?+
Notable localities include Orcesco, on Alpe Rosso, Val Vigezzo, Piedmont, Italy; Kovdor massif, Kola Peninsula, Russia.
Is vigezzite safe to handle?+
Vigezzite contains trace uranium or thorium. Contains uranium and thorium, handle with care and keep samples stored in a shielded container to minimize exposure to radiation.
What minerals are found with vigezzite?+
Vigezzite commonly co-occurs with Pyrochlore, Columbite, Fersmite. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does vigezzite form in?+
Where it forms: In miarolitic cavities in an albitized pegmatite in amphibolite and biotite gneiss (Orcesco, Italy). Working float back to the host body is the standard way to chase a fresh occurrence.
What is vigezzite used for?+
Vigezzite is used in collector.

Find vigezzite on the map

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