Calciodelrioite is a rare secondary vanadium mineral that typically forms thin, colorless to tan, platy crystal crusts or coatings. It is most commonly found as an efflorescence in the oxidized zones of uranium-vanadium mines in the Colorado Plateau, often associated with other vanadium-rich minerals.
Is this calciodelrioite?
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 calciodelrioite with a known reference. Calciodelrioite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: subadamantine (crystals), silky (aggregates).
- 4Match the color rangeCompare against the expected color range: colorless, tan, reddish brown, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: platy crystals.
Often confused with
Calciodelrioite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Calciodelrioite leaves white, Pascoite leaves cadmium-yellow; luster reads subadamantine (crystals), silky (aggregates) on Calciodelrioite and vitreous to subadamantine on Pascoite.
How to tell apart: Calciodelrioite is noticeably harder (Mohs 2.5 vs. ~1); streak differs, so Calciodelrioite leaves white, Hewettite leaves brownish red; luster reads subadamantine (crystals), silky (aggregates) on Calciodelrioite and silky to adamantine on Hewettite.
Often found alongside calciodelrioite
Minerals reported to co-occur with calciodelrioite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca(VO₃)₂·4H₂O
- Mohs hardness
- 2.5
- Density
- 2.451-2.503 g/cm³
- Streak
- White
- Luster
- Subadamantine (crystals), silky (aggregates)
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Platy crystals
- Cleavage
- Perfect on {001}, others possible parallel [100]
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral as crystalline crusts on fracture surfaces in the oxidized portions of corvusite- and montroseite-impregnated sandstone
Where rockhounds find calciodelrioite
Classic worldwide localities
- Uravan Mineral Belt, Colorado, USA
- La Sal District, Utah, USA
Field-hunting tip
Where it forms: A secondary mineral as crystalline crusts on fracture surfaces in the oxidized portions of corvusite- and montroseite-impregnated sandstone. If you start seeing gypsum, rossite, metarossite in float, you are in the right ground. Typical habit: platy crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify calciodelrioite?+
Where is calciodelrioite found?+
Is calciodelrioite safe to handle?+
What rocks look like calciodelrioite?+
What minerals are found with calciodelrioite?+
What kind of rock does calciodelrioite form in?+
What is calciodelrioite used for?+
Find calciodelrioite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
