Fluorcalciomicrolite is a complex tantalate mineral belonging to the pyrochlore supergroup. It typically appears as small, octahedral crystals in highly evolved granitic pegmatites and is prized by collectors for its radioactive chemistry and rare occurrence.

Hardness

5-5.5

Mohs

Luster

Resinous

Streak

Yellowish-white

Transparency

Translucent

mineralrarePyrochlore Supergroup family

Fluorcalciomicrolite

Hardness: 5-5.5
Luster: Resinous
Streak: Yellowish-white
Transparency: Translucent

No image

Is this fluorcalciomicrolite?

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 fluorcalciomicrolite with a known reference. Fluorcalciomicrolite sits at Mohs 5-5.5 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Fluorcalciomicrolite leaves a yellowish-white streak.
3
Read the luster
Hold the specimen under a strong light. Fluorcalciomicrolite typically shows a resinous luster.
4
Match the color range
Compare against the expected color range: yellow, brown, reddish-brown, black.
5
Look at form & habit
Crystal system: cubic. Typical habit: octahedral crystals.

Often found alongside fluorcalciomicrolite

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

All properties

Chemical formula: (Ca,Na,□)₂Ta₂O₆(F,OH)
Mohs hardness: 5-5.5
Density: 5.6-6.0 g/cm³
Colors: Yellow Brown Reddish-brown Black
Streak: Yellowish-white
Luster: Resinous
Transparency: Translucent
Crystal system: Cubic
Crystal habit: Octahedral Crystals
Cleavage: None
Rarity: Rare
Uses: Collector, Scientific Study
Host rock: Granite Pegmatites
Typical price: $50-500 depending on crystal size and quality

Where rockhounds find fluorcalciomicrolite

Classic worldwide localities

Sweden
Russia
Canada
Norway

Field-hunting tip

Look in granite pegmatites country — that is the host setting where fluorcalciomicrolite typically forms. If you start seeing albite, quartz, microcline in float, you are in the right ground. Field specimens usually show a octahedral crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify fluorcalciomicrolite?+

Mohs hardness is 5-5.5. It typically shows a resinous luster. The streak is yellowish-white. Common colors include yellow, brown, reddish-brown, black.

Where is fluorcalciomicrolite found?+

Notable localities include Sweden; Russia; Canada; Norway.

How much is fluorcalciomicrolite worth?+

Typical asking prices fall in the range of $50-500 depending on crystal size and quality. Quality, size, and provenance can move individual specimens well outside that range.

Is fluorcalciomicrolite safe to handle?+

This mineral is radioactive. Contains thorium and uranium which make it radioactive; handle with care and wash hands after contact. Handle with care, avoid grinding or breathing dust, and store separately.

What minerals are found with fluorcalciomicrolite?+

Fluorcalciomicrolite commonly co-occurs with Albite, Quartz, Microcline, Lepidolite, Beryl. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does fluorcalciomicrolite form in?+

Fluorcalciomicrolite typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is fluorcalciomicrolite used for?+

Fluorcalciomicrolite is used in collector, scientific study.

Find fluorcalciomicrolite on the map

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