Bicapite is a very rare uranyl sulfate-carbonate mineral known primarily from the Bica mine in Brazil. It typically forms delicate, platy yellow crystals that require careful handling due to its radioactive nature and solubility.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

Yellow

Transparency

Transparent

mineralrarenull family

Bicapite

Hardness: 2-3
Luster: Vitreous
Streak: Yellow
Transparency: Transparent

No image

Is this bicapite?

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 bicapite with a known reference. Bicapite sits at Mohs 2-3 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Bicapite leaves a yellow streak.
3
Read the luster
Hold the specimen under a strong light. Bicapite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: yellow, yellowish-green.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: platy crystals.

Often confused with

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

mineral

Andersonite

Mohs 2.5

How to tell apart: Streak differs — Bicapite leaves yellow, Andersonite leaves white.

How to tell apart: Streak differs — Bicapite leaves yellow, Grimselite leaves white.

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All properties

Chemical formula: K₂Na₂Mg₅(UO₂)₂(SO₄)₄(CO₃)₃(OH)₂·17H₂O
Mohs hardness: 2-3
Density: 3.32 g/cm³
Colors: Yellow Yellowish-green
Streak: Yellow
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Platy Crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins
Typical price: $50-300 thumbnail

Where rockhounds find bicapite

Classic worldwide localities

Bica mine, Brazil

Field-hunting tip

Look in hydrothermal veins country — that is the host setting where bicapite typically forms. If you start seeing uranyl carbonates, sulfates in float, you are in the right ground. Field specimens usually show a platy crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify bicapite?+

Mohs hardness is 2-3. It typically shows a vitreous luster. The streak is yellow. Common colors include yellow, yellowish-green.

Where is bicapite found?+

Notable localities include Bica mine, Brazil.

How much is bicapite worth?+

Typical asking prices fall in the range of $50-300 thumbnail. Quality, size, and provenance can move individual specimens well outside that range.

Is bicapite safe to handle?+

This mineral is radioactive. It contains toxic constituents. This mineral contains uranium and is radioactive; handle with care using gloves and store in a lead-lined container away from living areas. Avoid inhaling dust or ingestion. Handle with care, avoid grinding or breathing dust, and store separately.

What rocks look like bicapite?+

Bicapite is most often confused with Andersonite, Grimselite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with bicapite?+

Bicapite commonly co-occurs with Uranyl carbonates, Sulfates. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does bicapite form in?+

Bicapite typically forms in hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is bicapite used for?+

Bicapite is used in collector.

Find bicapite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.