Cabvinite is a rare thorium hydroxide that forms white square prismatic crystals. It occurs in low-temperature hydrothermal alteration of Mo-Bi mineralization. It was first described from Mo-Bi ore deposit of Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy.

Hardness
4
Mohs
Luster
Vitreous
Streak
White
Transparency
Transparent

Is this cabvinite?

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 cabvinite with a known reference. Cabvinite sits at Mohs 4, 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: vitreous.
  • 4
    Match the color range
    Compare against the expected color range: white.
  • 5
    Look at form & habit
    Crystal system: tetragonal. Typical habit: square prismatic crystals.

Often confused with

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

Often found alongside cabvinite

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

All properties

Chemical formula
Th₂F₇(OH)·3H₂O
Mohs hardness
4
Density
5.35 g/cm³
Colors
Streak
White
Luster
Vitreous
Transparency
Transparent
Crystal system
Tetragonal
Crystal habit
Square prismatic crystals
Cleavage
Cleavage or parting on {001} suggested by SEM images
Rarity
Rare
Uses
Collector
Host rock
From low-temperature hydrothermal alteration of Mo-Bi mineralization

Where rockhounds find cabvinite

Classic worldwide localities

  • Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy

Field-hunting tip

Where it forms: From low-temperature hydrothermal alteration of Mo-Bi mineralization. If you start seeing brookite, iron oxy-hydroxide in float, you are in the right ground. Typical habit: square prismatic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify cabvinite?+
Mohs hardness is 4. Luster: vitreous. The streak is white. Common colors include white.
Where is cabvinite found?+
Notable localities include Su Seinargiu, Sarroch, Cagliari, Sardinia, Italy.
Is cabvinite safe to handle?+
Cabvinite contains uranium or thorium and calls for real care. Contains thorium and is radioactive; store it apart from other specimens. Wash hands thoroughly after handling and avoid creating dust.
What rocks look like cabvinite?+
Cabvinite is most often confused with Wollastonite, Apophyllite. A quick hardness test and a streak check separate the look-alikes faster than color alone.
What minerals are found with cabvinite?+
Cabvinite commonly co-occurs with Brookite, Iron oxy-hydroxide. Spotting any of these in float or country rock is a useful trip signal.
What kind of rock does cabvinite form in?+
Where it forms: From low-temperature hydrothermal alteration of Mo-Bi mineralization. Working float back to the host body is the standard way to chase a fresh occurrence.
What is cabvinite used for?+
Cabvinite is used in collector.

Find cabvinite on the map

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