Ferrivauxite is an extremely rare phosphate mineral typically found as radial sprays of yellow, bladed crystals. It is almost exclusively found in association with other rare secondary phosphate minerals in the tin-rich mines of Bolivia. Collectors prize it for its delicate habit and restricted occurrence in phosphate-rich mineral assemblages.
Is this ferrivauxite?
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 ferrivauxite with a known reference. Ferrivauxite 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. Ferrivauxite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Ferrivauxite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: yellow, brownish yellow.
- 5Look at form & habitCrystal system: triclinic. Typical habit: radial aggregates of bladed crystals, crusts.
Often confused with
Ferrivauxite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside ferrivauxite
Minerals reported to co-occur with ferrivauxite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Fe²⁺Al₂(PO₄)₂(OH)₂·6H₂O
- Mohs hardness
- 3.5
- Density
- 2.4-2.5 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Radial Aggregates of Bladed Crystals, Crusts
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Hydrothermal Tin Deposits in Sedimentary or Igneous Rocks
- Typical price
- $50-300 per specimen depending on quality and size
Where rockhounds find ferrivauxite
Classic worldwide localities
- Siglo XX Mine, Bolivia
- Llallagua, Bolivia
Field-hunting tip
Look in hydrothermal tin deposits in sedimentary or igneous rocks country — that is the host setting where ferrivauxite typically forms. If you start seeing vauxite, paravauxite, metavauxite in float, you are in the right ground. Field specimens usually show a radial aggregates of bladed crystals, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find ferrivauxite on the map
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