Lermontovite is a rare, radioactive uranium phosphate mineral typically found as earthy or botryoidal crusts in hydrothermal uranium deposits. Due to its radioactive nature, it is primarily sought after by advanced collectors of uranium-bearing species.
Is this lermontovite?
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 lermontovite with a known reference. Lermontovite sits at Mohs 3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: light green.
- 3Read the lusterHold the specimen under a strong light. Luster: dull, silky on fractures.
- 4Match the color rangeCompare against the expected color range: gray green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: botryoidal, massive, crusts.
Often confused with
Lermontovite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Lermontovite leaves light green, Autunite leaves pale yellow; luster reads dull, silky on fractures on Lermontovite and vitreous, pearly on {001} on Autunite.
How to tell apart: Streak differs, so Lermontovite leaves light green, Torbernite leaves pale green; luster reads dull, silky on fractures on Lermontovite and vitreous, subadamantine, waxy, pearly on cleavages; becoming dull on dehydration to metatorbernite on Torbernite.
Often found alongside lermontovite
Minerals reported to co-occur with lermontovite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- UPO₄(OH)·H₂O
- Mohs hardness
- 3
- Density
- 4.00-4.50 g/cm³
- Colors
- Streak
- Light green
- Luster
- Dull, silky on fractures
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Botryoidal, massive, crusts
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- In uranium-bearing veins in a granite porphyry stock
Where rockhounds find lermontovite
Classic worldwide localities
- Beshtau uranium deposit, near Pyatigorsk, northern Caucasus Mountains, Russia
Field-hunting tip
Where it forms: In uranium-bearing veins in a granite porphyry stock. If you start seeing halloysite, vrbaite, lorandite in float, you are in the right ground. Typical habit: botryoidal, massive, crusts. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify lermontovite?+
Where is lermontovite found?+
Is lermontovite safe to handle?+
What rocks look like lermontovite?+
What minerals are found with lermontovite?+
What kind of rock does lermontovite form in?+
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Find lermontovite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
