Smirnovskite is a rare radioactive phosphate-silicate mineral typically found as resinous, yellow to brown massive aggregates. It is primarily identified through its association with specific pegmatite environments and its significant thorium content.
Is this smirnovskite?
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 smirnovskite with a known reference. Smirnovskite sits at Mohs 4-5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: yellowish-white.
- 3Read the lusterHold the specimen under a strong light. Luster: resinous.
- 4Match the color rangeCompare against the expected color range: yellow, brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: massive, aggregates.
Often confused with
Smirnovskite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Smirnovskite leaves yellowish-white, Monazite leaves white.
How to tell apart: Streak differs, so Smirnovskite leaves yellowish-white, Thorite leaves light orange to dark brown; luster reads resinous on Smirnovskite and vitreous to resinous or greasy on Thorite.
Often found alongside smirnovskite
Minerals reported to co-occur with smirnovskite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Th,Ca)PO₄·nH₂O
- Mohs hardness
- 4-5
- Density
- 4.8-5.0 g/cm³
- Streak
- Yellowish-white
- Luster
- Resinous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Massive, aggregates
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Granite pegmatites
Where rockhounds find smirnovskite
Classic worldwide localities
- Eastern Siberia, Russia
- Transbaikalia, Russia
Field-hunting tip
Where it forms: Granite pegmatites. If you start seeing quartz, feldspar, mica in float, you are in the right ground. Typical habit: massive, aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify smirnovskite?+
Where is smirnovskite found?+
Is smirnovskite safe to handle?+
What rocks look like smirnovskite?+
What minerals are found with smirnovskite?+
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Find smirnovskite on the map
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