Calderónite is a rare lead-iron vanadate mineral that typically forms as small, platy yellow crystals or crusts within oxidized zones of base metal deposits. It is most notably associated with the famous Mina Ojuela in Mexico, where it was first discovered and named. Collectors should look for its distinctive resinous luster and yellow color when examining specimens from oxidized ore bodies.
Is this calderónite?
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 calderónite with a known reference. Calderónite 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: red.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to resinous (if altered).
- 4Match the color rangeCompare against the expected color range: reddish orange, reddish brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic, striated, tabular.
Often confused with
Calderónite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Calderónite leaves red, Descloizite leaves orange to brownish red; luster reads vitreous to resinous (if altered) on Calderónite and greasy on Descloizite.
How to tell apart: Streak differs, so Calderónite leaves red, Mottramite leaves yellowish green; luster reads vitreous to resinous (if altered) on Calderónite and greasy on Mottramite.
How to tell apart: Streak differs, so Calderónite leaves red, Vanadinite leaves white to pale red or pale yellow; luster reads vitreous to resinous (if altered) on Calderónite and subresinous to subadamantine on Vanadinite.
Often found alongside calderónite
Minerals reported to co-occur with calderónite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Pb₂Fe³⁺(VO₄)₂OH
- Mohs hardness
- 3-4
- Density
- 6.04 g/cm³
- Streak
- Red
- Luster
- Vitreous to resinous (if altered)
- Transparency
- Semitransparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic, striated, tabular
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the upper oxidation zone of Pb-Zn hydrothermal deposits
Where rockhounds find calderónite
Classic worldwide localities
- Las Colmenitas and Los Llanos mine, 2 km northwest of Santa Marta (type locality) and the La Muda mine, Azuaga, Badajoz province, Spain
Field-hunting tip
Where it forms: In the upper oxidation zone of Pb-Zn hydrothermal deposits. If you start seeing mottramite, descloizite, vanadinite in float, you are in the right ground. Typical habit: prismatic, striated, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
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Find calderónite on the map
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