Biphosphammite is a rare, water-soluble ammonium phosphate mineral typically found as white crusts or efflorescences in guano deposits. It is extremely fragile and hygroscopic, often requiring airtight storage to prevent dissolution by atmospheric moisture.
Is this biphosphammite?
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 biphosphammite with a known reference. Biphosphammite sits at Mohs 1-2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white to pale buff.
- 3Read the lusterHold the specimen under a strong light. Luster: dull, earthy; crystals rarely vitreous.
- 4Match the color rangeCompare against the expected color range: brown, colorless, gray white.
- 5Look at form & habitCrystal system: tetragonal. Typical habit: crusts, efflorescent coatings.
Often confused with
Biphosphammite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads dull, earthy; crystals rarely vitreous on Biphosphammite and vitreous to dull on Mascagnite.
How to tell apart: Luster reads dull, earthy; crystals rarely vitreous on Biphosphammite and vitreous on Struvite.
Often found alongside biphosphammite
Minerals reported to co-occur with biphosphammite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (NH₄)(H₂PO₄)
- Mohs hardness
- 1-2
- Density
- 2.04 g/cm³
- Colors
- Streak
- White to pale buff
- Luster
- Dull, earthy; crystals rarely vitreous
- Transparency
- Semitransparent
- Crystal system
- Tetragonal
- Crystal habit
- Crusts, efflorescent coatings
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- An alteration product of phosphammite in guano, due to loss of NH4 (Guañape Island, Peru); a byproduct of the reaction between the liquid fraction of bat guano and urea (Murra-el-elevyn Cave, Australia)
Where rockhounds find biphosphammite
Classic worldwide localities
- Guañape Island, south of Trujillo, Peru
- Murra-el-elevyn Cave, Cocklebiddy, and in Petrogale Cave, near Madura, Western Australia
- Gcwihaba Cave, 280 km west of Maun, northwestern Botswana
Field-hunting tip
Where it forms: An alteration product of phosphammite in guano, due to loss of NH4 (Guañape Island, Peru); a byproduct of the reaction between the liquid fraction of bat guano and urea (Murra-el-elevyn Cave, Australia). If you start seeing phosphammite, syngenite in float, you are in the right ground. Typical habit: crusts, efflorescent coatings. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify biphosphammite?+
Where is biphosphammite found?+
What rocks look like biphosphammite?+
What minerals are found with biphosphammite?+
What kind of rock does biphosphammite form in?+
What is biphosphammite used for?+
Find biphosphammite on the map
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