Serrabrancaite is a rare manganese phosphate mineral found in phosphate-rich pegmatites. It typically occurs as small, pale, tabular crystals or crusts and is identified by its association with secondary phosphate minerals in the Brazilian localities where it was first discovered.
Is this serrabrancaite?
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 serrabrancaite with a known reference. Serrabrancaite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Serrabrancaite leaves a olive-green streak.
- 3Read the lusterHold the specimen under a strong light. Serrabrancaite typically shows a adamantine luster.
- 4Match the color rangeCompare against the expected color range: dark brown, dark greenish black.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, aggregates.
Often confused with
Serrabrancaite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Serrabrancaite leaves olive-green, Heterosite leaves light violet to brownish-purple; luster reads adamantine on Serrabrancaite and dull to earthy on Heterosite.
How to tell apart: Streak differs, so Serrabrancaite leaves olive-green, Triphylite leaves white; luster reads adamantine on Serrabrancaite and vitreous on Triphylite.
Often found alongside serrabrancaite
Minerals reported to co-occur with serrabrancaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MnPO₄·H₂O
- Mohs hardness
- 3.5
- Density
- 3.37 g/cm³
- Streak
- Olive-green
- Luster
- Adamantine
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Aggregates
- Cleavage
- Poor
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite Pegmatites
Where rockhounds find serrabrancaite
Classic worldwide localities
- Serra Branca pegmatite, Paraíba, Brazil
Field-hunting tip
Look in granite pegmatites country, the host setting where serrabrancaite typically forms. If you start seeing triphylite, hureaulite, roscherite in float, you are in the right ground. Field specimens usually show a tabular crystals, aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify serrabrancaite?+
Where is serrabrancaite found?+
What rocks look like serrabrancaite?+
What minerals are found with serrabrancaite?+
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Find serrabrancaite on the map
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