Kokinosite is a rare vanadium-bearing mineral typically found as thin, orange to yellow platy coatings or small crusts on sandstone. It is most commonly associated with secondary uranium-vanadium mineral deposits found in the Colorado Plateau region of the United States.
Is this kokinosite?
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 kokinosite with a known reference. Kokinosite sits at Mohs ~1.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellow.
- 3Read the lusterHold the specimen under a strong light. Luster: subadamantine.
- 4Match the color rangeCompare against the expected color range: yellow-orange.
- 5Look at form & habitCrystal system: triclinic. Typical habit: platy crystals, crusts.
Often confused with
Kokinosite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Pascoite is the harder of the two (Mohs ~2.5 vs. ~1.5); streak differs, so Kokinosite leaves yellow, Pascoite leaves cadmium-yellow; luster reads subadamantine on Kokinosite and vitreous to subadamantine on Pascoite.
How to tell apart: Streak differs, so Kokinosite leaves yellow, Hewettite leaves brownish red; luster reads subadamantine on Kokinosite and silky to adamantine on Hewettite.
Often found alongside kokinosite
Minerals reported to co-occur with kokinosite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Ca₂[V₁₀O₂₈]·24H₂O
- Mohs hardness
- ~1.5
- Density
- 2.35 g/cm³
- Colors
- Streak
- Yellow
- Luster
- Subadamantine
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Platy crystals, crusts
- Cleavage
- Good on {011̄}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a moist part of the oxidation zone of a corvusite-montroseite-bearing sandstone
Where rockhounds find kokinosite
Classic worldwide localities
- St. Jude mine, Gypsum Valley, Slick Rock district, San Miguel County, Colorado, USA
Field-hunting tip
Where it forms: In a moist part of the oxidation zone of a corvusite-montroseite-bearing sandstone. If you start seeing gypsum, huemulite, metarossite in float, you are in the right ground. Typical habit: platy crystals, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
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Find kokinosite on the map
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