Tinnunculite is an organic mineral that forms in guano deposits, often resulting from the interaction between falcon guano and surrounding rocks. It typically appears as small, crusty, or powdery white masses and is prized by specialized mineral collectors for its unique organic composition.
Is this tinnunculite?
4-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 tinnunculite with a known reference. Tinnunculite sits at Mohs 2, softer than the next harder reference, harder than the previous one.
- 2Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 3Match the color rangeCompare against the expected color range: white.
- 4Look at form & habitCrystal system: monoclinic. Typical habit: microcrystalline crusts, earthy aggregates.
Often confused with
Tinnunculite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside tinnunculite
Minerals reported to co-occur with tinnunculite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- C₅H₄N₄O₃·2H₂O
- Mohs hardness
- 2
- Density
- 1.73 g/cm³
- Colors
- Luster
- Vitreous
- Transparency
- Transparent to translucent
- Crystal system
- Monoclinic
- Crystal habit
- Microcrystalline crusts, earthy aggregates
- Cleavage
- Distinct on {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- From the crystallization of uric acid in bird excrement in a cold and humid Arctic climate (Kola) or through reaction with hot gases on a burning coal mine slagheap (South Urals)
Where rockhounds find tinnunculite
Classic worldwide localities
- Mt. Rasvumchorr, Khibiny complex and Mts. Alluaiv and Vavdbed, Lovozero complex, Kola Peninsula, Russia
- Dumps of coal shaft #44, Kopeisk, near Chelyabinsk, South Urals, Russia
Field-hunting tip
Where it forms: From the crystallization of uric acid in bird excrement in a cold and humid Arctic climate (Kola) or through reaction with hot gases on a burning coal mine slagheap (South Urals). If you start seeing weddellite, uricite in float, you are in the right ground. Typical habit: microcrystalline crusts, earthy aggregates. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify tinnunculite?+
Where is tinnunculite found?+
What rocks look like tinnunculite?+
What minerals are found with tinnunculite?+
What kind of rock does tinnunculite form in?+
What is tinnunculite used for?+
Find tinnunculite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
