Simplotite is a rare hydrous calcium vanadate typically found as thin, black to greenish black coatings or small platy crystals in oxidized uranium-vanadium deposits. It is specifically identified by its association with other secondary vanadium minerals in the sandstone of the Colorado Plateau. Due to its softness and rarity, it is primarily sought after by advanced mineral collectors specializing in vanadium species.
Is this simplotite?
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 simplotite with a known reference. Simplotite sits at Mohs ~1, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brownish black.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: black, greenish black, dark green.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: micaceous, platy.
Often confused with
Simplotite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Corvusite is the harder of the two (Mohs 2.5-3 vs. ~1); streak differs, so Simplotite leaves brownish black, Corvusite leaves purplish blue-black; luster reads vitreous on Simplotite and “lusterous” on Corvusite.
How to tell apart: Luster reads vitreous on Simplotite and silky to adamantine on Hewettite.
Often found alongside simplotite
Minerals reported to co-occur with simplotite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaV₄O₉·5H₂O
- Mohs hardness
- ~1
- Density
- 2.64 g/cm³
- Streak
- Brownish black
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Micaceous, platy
- Cleavage
- {010}, perfect, micaceous
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A secondary mineral on fracture surfaces and replacing fossil wood in Colorado Plateau-type U–V deposits
Where rockhounds find simplotite
Classic worldwide localities
- Sundown Claim, San Miguel County, Utah, USA (type locality)
Field-hunting tip
Where it forms: A secondary mineral on fracture surfaces and replacing fossil wood in Colorado Plateau-type U–V deposits. If you start seeing montroseite, duttonite, melanovanadite in float, you are in the right ground. Typical habit: micaceous, platy. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify simplotite?+
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Find simplotite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
