Mendozavilite-KCa is a rare molybdophosphate mineral typically found as a secondary oxidation product in arid molybdenum deposits. Collectors should look for earthy, yellow to orange crusts or powdery coatings associated with molybdenum ores, often requiring magnification for identification.
Is this mendozavilite-kca?
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-kca with a known reference. Mendozavilite-KCa sits at Mohs ~2.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: very pale greenish yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to subadamantine.
- 4Match the color rangeCompare against the expected color range: greenish yellow.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, powdery, or as fine-grained efflorescences.
Often confused with
Mendozavilite-KCa vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Mendozavilite-KCa leaves very pale greenish yellow, Ferrimolybdite leaves pale yellow; luster reads vitreous to subadamantine on Mendozavilite-KCa and adamantine to silky, earthy on Ferrimolybdite.
How to tell apart: Lindgrenite is the harder of the two (Mohs 4.5 vs. ~2.5); streak differs, so Mendozavilite-KCa leaves very pale greenish yellow, Lindgrenite leaves light green; luster reads vitreous to subadamantine on Mendozavilite-KCa and greasy on Lindgrenite.
Often found alongside mendozavilite-kca
Minerals reported to co-occur with mendozavilite-kca. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- [K₂(H₂O)₁₅Ca(H₂O)₆][Mo₈P₂Fe₃O₃₄(OH)₃]
- Mohs hardness
- ~2.5
- Density
- 2.79 g/cm³
- Colors
- Streak
- Very pale greenish yellow
- Luster
- Vitreous to subadamantine
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, powdery, or as fine-grained efflorescences
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidized zone of a porphyry copper deposit
Where rockhounds find mendozavilite-kca
Classic worldwide localities
- Chuquicamata mine, Antofagasta, Chile
Field-hunting tip
Where it forms: In the oxidized zone of a porphyry copper deposit. If you start seeing quartz, jarosite in float, you are in the right ground. Typical habit: massive, powdery, or as fine-grained efflorescences. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify mendozavilite-kca?+
Where is mendozavilite-kca found?+
What rocks look like mendozavilite-kca?+
What minerals are found with mendozavilite-kca?+
What kind of rock does mendozavilite-kca form in?+
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Find mendozavilite-kca on the map
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