Bicapite is a very rare potassium sodium magnesium polyvanadate known primarily from the Bica mine in Brazil. It typically forms delicate, platy dark red-brown to appearing black crystals that require careful handling due to its radioactive nature and solubility.

Hardness

2-3

Mohs

Luster

Vitreous

Streak

Orange

Transparency

Translucent

mineralrare

Bicapite

Hardness: 2-3
Luster: Vitreous
Streak: Orange
Transparency: Translucent

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 orange 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: dark red-brown, appearing black.
5
Look at form & habit
Crystal system: tetragonal. 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, so Bicapite leaves orange, Andersonite leaves white.

How to tell apart: Streak differs, so Bicapite leaves orange, Grimselite leaves pale yellow.

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All properties

Chemical formula: KNa₂Mg₂(H₂PV⁵⁺₁₄O₄₂)·25H₂O
Mohs hardness: 2-3
Density: 2.44 g/cm³
Colors: Dark Red-brown Appearing Black
Streak: Orange
Luster: Vitreous
Transparency: Translucent
Crystal system: Tetragonal
Crystal habit: Platy Crystals
Cleavage: Excellent On {100}
Rarity: Rare
Uses: Collector
Host rock: Hydrothermal Veins

Where rockhounds find bicapite

Classic worldwide localities

Bica mine, Brazil

Field-hunting tip

Look in hydrothermal veins country, 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 orange. Common colors include dark red-brown, appearing black.

Where is bicapite found?+

Notable localities include Bica mine, Brazil.

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.