Cesplumtantite is a very rare cesium-rich tantalum mineral found in highly evolved granite pegmatites. It typically occurs as small, colorless to pale yellow tabular crystals embedded within or associated with other pegmatite minerals.

Hardness

5-6

Mohs

Luster

Adamantine

Streak

White

Transparency

Transparent

mineralrare

Cesplumtantite

Hardness: 5-6
Luster: Adamantine
Streak: White
Transparency: Transparent

Is this cesplumtantite?

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 cesplumtantite with a known reference. Cesplumtantite sits at Mohs 5-6, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Cesplumtantite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Cesplumtantite typically shows a adamantine luster.
4
Match the color range
Compare against the expected color range: colorless, white, pale yellow.
5
Look at form & habit
Crystal system: tetragonal. Typical habit: tabular crystals.

Often found alongside cesplumtantite

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

All properties

Chemical formula: (Cs,Na)₂(Pb,Sb³⁺)₃Ta₈O₂₄
Mohs hardness: 5-6
Density: 6.68 g/cm³
Colors: Colorless White Pale Yellow
Streak: White
Luster: Adamantine
Transparency: Transparent
Crystal system: Tetragonal
Crystal habit: Tabular Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites

Where rockhounds find cesplumtantite

Classic worldwide localities

Manono, Shaba, Democratic Republic of Congo

Field-hunting tip

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

Common questions

How do you identify cesplumtantite?+

Mohs hardness is 5-6. It typically shows a adamantine luster. The streak is white. Common colors include colorless, white, pale yellow.

Where is cesplumtantite found?+

Notable localities include Manono, Shaba, Democratic Republic of Congo.

Is cesplumtantite safe to handle?+

It contains toxic constituents. Contains lead and antimony; wash hands thoroughly after handling and avoid inhaling dust. Handle with care, avoid grinding or breathing dust, and store separately.

What minerals are found with cesplumtantite?+

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

What kind of rock does cesplumtantite form in?+

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

What is cesplumtantite used for?+

Cesplumtantite is used in collector.

Find cesplumtantite on the map

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