Bobierrite is a rare magnesium phosphate mineral typically found in guano deposits where it forms delicate, pearly tabular crystals. It is chemically similar to vivianite but lacks iron, often occurring as white or colorless radiating sprays or crusts associated with other secondary phosphates.
Is this bobierrite?
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 bobierrite with a known reference. Bobierrite sits at Mohs 2 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Bobierrite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Bobierrite typically shows a pearly luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, yellowish.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: tabular crystals, radiating aggregates, crusts.
Often confused with
Bobierrite vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Bobierrite leaves white, Vivianite leaves white to light blue; luster reads pearly on Bobierrite and vitreous on Vivianite.
How to tell apart: Luster reads pearly on Bobierrite and vitreous on Newberyite.
Often found alongside bobierrite
Minerals reported to co-occur with bobierrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₃(PO₄)₂·8H₂O
- Mohs hardness
- 2
- Density
- 2.19 g/cm³
- Streak
- White
- Luster
- Pearly
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Tabular Crystals, Radiating Aggregates, Crusts
- Cleavage
- Perfect On {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Phosphate-rich Guano Deposits
- Typical price
- $20-150 per specimen
Where rockhounds find bobierrite
Classic worldwide localities
- Yukon, Canada
- Bavaria, Germany
- Victoria, Australia
Field-hunting tip
Look in phosphate-rich guano deposits country — that is the host setting where bobierrite typically forms. If you start seeing vivianite, newberyite, brushite in float, you are in the right ground. Field specimens usually show a tabular crystals, radiating aggregates, crusts habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find bobierrite on the map
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