Carlosbarbosaite is a rare uranyl niobate mineral typically found as small, bright yellow acicular or prismatic crystals. It is primarily known from its type locality in Brazil, where it occurs within granitic pegmatites. Collectors should treat it with caution due to its uranium content.
Is this carlosbarbosaite?
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 carlosbarbosaite with a known reference. Carlosbarbosaite sits at Mohs 3-4, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellowish white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: cream, pale yellow.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: acicular to prismatic crystals.
Often confused with
Carlosbarbosaite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside carlosbarbosaite
Minerals reported to co-occur with carlosbarbosaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (UO₂)₂Nb₂O₆(OH)₂·2H₂O
- Mohs hardness
- 3-4
- Density
- 4.713 g/cm³
- Colors
- Streak
- Yellowish white
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Acicular to prismatic crystals
- Cleavage
- Presumed to be {100} and {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A late-stage cavity filling in albite in a complex pegmatite
Where rockhounds find carlosbarbosaite
Classic worldwide localities
- Jaguaraçu pegmatite, Minas Gerais, Brazil
Field-hunting tip
Where it forms: A late-stage cavity filling in albite in a complex pegmatite. If you start seeing albite, muscovite, zircon in float, you are in the right ground. Typical habit: acicular to prismatic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify carlosbarbosaite?+
Where is carlosbarbosaite found?+
Is carlosbarbosaite safe to handle?+
What rocks look like carlosbarbosaite?+
What minerals are found with carlosbarbosaite?+
What kind of rock does carlosbarbosaite form in?+
What is carlosbarbosaite used for?+
Find carlosbarbosaite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
