Hendersonite is a rare calcium-vanadium hydrated oxide found primarily in the Colorado Plateau's sandstone-hosted ore deposits. It typically occurs as dark brown to black earthy crusts or coatings on fractures, making it challenging to identify without analytical testing. Collectors generally find it as a secondary mineral associated with other vanadium-rich species.
Is this hendersonite?
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 hendersonite with a known reference. Hendersonite 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: dark brownish green.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous, pearly to subadamantine.
- 4Match the color rangeCompare against the expected color range: greenish black, black.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: bladed, fibrous, microscopic crystals.
Often confused with
Hendersonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Hendersonite leaves dark brownish green, Corvusite leaves purplish blue-black; luster reads vitreous, pearly to subadamantine on Hendersonite and “lusterous” on Corvusite.
How to tell apart: Montroseite is the harder of the two (Mohs 5.5-6.5 vs. 2.5); streak differs, so Hendersonite leaves dark brownish green, Montroseite leaves black; luster reads vitreous, pearly to subadamantine on Hendersonite and submetallic on Montroseite.
Often found alongside hendersonite
Minerals reported to co-occur with hendersonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaV₆O₁₆·6H₂O
- Mohs hardness
- 2.5
- Density
- 2.77-2.79 g/cm³
- Colors
- Streak
- Dark brownish green
- Luster
- Vitreous, pearly to subadamantine
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Bladed, fibrous, microscopic crystals
- Cleavage
- Perfect k crystal platiness
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In thin seams and veinlets through sandstone at the interface between partially oxidized and unoxidized ore in Colorado Plateau-type U–V deposits
Where rockhounds find hendersonite
Classic worldwide localities
- J.J. mine, Paradox Valley, Uravan district, Montrose Co., Colorado, USA
- Nelson mine, Eastside mines, Carrizo Mountains, San Juan Co., New Mexico, USA
Field-hunting tip
Where it forms: In thin seams and veinlets through sandstone at the interface between partially oxidized and unoxidized ore in Colorado Plateau-type U–V deposits. If you start seeing paramontroseite, simplotite, melanovanadite in float, you are in the right ground. Typical habit: bladed, fibrous, microscopic crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find hendersonite on the map
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