Simplotite is a rare hydrous calcium vanadate typically found as thin, dark brown 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. Simplotite leaves a brown streak.
- 3Read the lusterHold the specimen under a strong light. Simplotite typically shows a dull luster.
- 4Match the color rangeCompare against the expected color range: dark brown, blackish-brown.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy crystals, crusts, earthy aggregates.
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 vs. 1); streak differs — Simplotite leaves brown, Corvusite leaves black.
How to tell apart: Streak differs — Simplotite leaves brown, Hewettite leaves brownish red; luster reads dull on Simplotite and pearly 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
- 2.8 g/cm³
- Colors
- Streak
- Brown
- Luster
- Dull
- Transparency
- Opaque
- Crystal system
- Triclinic
- Crystal habit
- Platy Crystals, Crusts, Earthy Aggregates
- Cleavage
- Perfect in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Sandstone Hosted Uranium-vanadium Deposits
- Typical price
- $20-150 for rare specimen fragments
Where rockhounds find simplotite
Classic worldwide localities
- Colorado Plateau, USA
- Montrose County, Colorado, USA
- San Juan County, Utah, USA
Field-hunting tip
Look in sandstone hosted uranium-vanadium deposits country — that is the host setting where simplotite typically forms. If you start seeing tyuyamunite, carnotite, hewettite in float, you are in the right ground. Field specimens usually show a platy crystals, crusts, earthy aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find simplotite on the map
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