Oxammite is an extremely rare organic mineral found primarily in guano deposits on islands where it forms through the reaction of bird excrement with phosphate-rich environments. It typically appears as white, crumbly crusts or small crystalline efflorescences that are highly susceptible to dissolution in water or humidity.
Is this oxammite?
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 oxammite with a known reference. Oxammite 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. Oxammite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Oxammite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: crusts, efflorescences, or tiny granular aggregates.
Often confused with
Oxammite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside oxammite
Minerals reported to co-occur with oxammite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (NH₄)₂C₂O₄·H₂O
- Mohs hardness
- 2.5
- Density
- 1.78 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Crusts, Efflorescences, Or Tiny Granular Aggregates
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Guano Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find oxammite
Classic worldwide localities
- Guañape Islands, Peru
- Ichaboe Island, Namibia
Field-hunting tip
Look in guano deposits country — that is the host setting where oxammite typically forms. If you start seeing guanine, struvite, phosphammite in float, you are in the right ground. Field specimens usually show a crusts, efflorescences, or tiny granular aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify oxammite?+
Where is oxammite found?+
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Find oxammite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
