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.
Is this bicapite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch bicapite with a known reference. Bicapite sits at Mohs 1.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: orange.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: dark red-brown, often appearing black.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: platy crystals.
Often confused with
Bicapite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Andersonite is the harder of the two (Mohs 2.5 vs. 1.5); streak differs, so Bicapite leaves orange, Andersonite leaves white.
How to tell apart: Streak differs, so Bicapite leaves orange, Grimselite leaves pale yellow.
Often found alongside bicapite
Minerals reported to co-occur with bicapite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KNa₂Mg₂(H₂PV⁵⁺₁₄O₄₂)·25H₂O
- Mohs hardness
- 1.5
- Density
- 2.44 g/cm³
- Colors
- Dark red-brownOften 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
- Formed by the oxidation of montroseite-corvusite assemblages in a moist environment on sandstone in a Colorado Plateau type, roll-front uranium/vanadium deposit
Where rockhounds find bicapite
Classic worldwide localities
- Pickett Corral mine, Bull Canyon, Montrose County, Colorado, USA
Field-hunting tip
Where it forms: Formed by the oxidation of montroseite-corvusite assemblages in a moist environment on sandstone in a Colorado Plateau type, roll-front uranium/vanadium deposit. If you start seeing gypsum, huemulite, thenardite in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bicapite?+
Where is bicapite found?+
Is bicapite safe to handle?+
What rocks look like bicapite?+
What minerals are found with bicapite?+
What kind of rock does bicapite form in?+
What is bicapite used for?+
Find bicapite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
