Mendozavilite-NaFe is a rare phosphate-molybdate mineral typically found as a secondary oxidation product in molybdenum-rich ore deposits. Collectors primarily find it as thin, dusty, or earthy yellow-to-orange coatings on host rock rather than distinct large crystals.
Is this mendozavilite-nafe?
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 mendozavilite-nafe with a known reference. Mendozavilite-NaFe 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: bright yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: empire yellow, orange.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: powdery, earthy crusts, microcrystalline aggregates.
Often confused with
Mendozavilite-NaFe vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Mendozavilite-KCa is the harder of the two (Mohs ~2.5 vs. 1.5); streak differs, so Mendozavilite-NaFe leaves bright yellow, Mendozavilite-KCa leaves very pale greenish yellow.
How to tell apart: Streak differs, so Mendozavilite-NaFe leaves bright yellow, Ferrimolybdite leaves pale yellow; luster reads vitreous on Mendozavilite-NaFe and adamantine to silky, earthy on Ferrimolybdite.
Often found alongside mendozavilite-nafe
Minerals reported to co-occur with mendozavilite-nafe. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- [Na₂(H₂O)₁₅Fe(H₂O)₆][Mo₈P₂Fe₃O₃₅(OH)₂]
- Mohs hardness
- 1.5
- Density
- 3.85 g/cm³
- Colors
- Empire yellowOrange
- Streak
- Bright yellow
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Powdery, earthy crusts, microcrystalline aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidized zone of some molybdenum-bearing hydrothermal mineral deposits
Where rockhounds find mendozavilite-nafe
Classic worldwide localities
- San Judas mine, Cumobabi molybdenum deposit, southwest of Cumpas, Sonora, Mexico
- Lomas Bayas mine, 93 km east northeast of Antofagasta, Antofagasta Province, Chile
Field-hunting tip
Where it forms: In the oxidized zone of some molybdenum-bearing hydrothermal mineral deposits. If you start seeing quartz, paramendozavilite in float, you are in the right ground. Typical habit: powdery, earthy crusts, microcrystalline aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mendozavilite-nafe?+
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What rocks look like mendozavilite-nafe?+
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Find mendozavilite-nafe on the map
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