Brianite is an exceptionally rare phosphate mineral primarily known from iron meteorites. It typically appears as small, colorless to pale yellow equant crystals associated with other extraterrestrial minerals like farringtonite and stanfieldite.
Is this brianite?
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 brianite with a known reference. Brianite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: equant to tabular crystals.
Often confused with
Brianite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside brianite
Minerals reported to co-occur with brianite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂CaMg(PO₄)₂
- Mohs hardness
- 4.5
- Density
- 3.0-3.3 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Equant to tabular crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- A very rare component in phosphate nodules in an iron meteorite
Where rockhounds find brianite
Classic worldwide localities
- In the Dayton finest (very fine-grained) octahedrite meteorite (type locality)
Field-hunting tip
Where it forms: A very rare component in phosphate nodules in an iron meteorite. If you start seeing panethite, whitlockite, albite in float, you are in the right ground. Typical habit: equant to tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify brianite?+
Where is brianite found?+
What rocks look like brianite?+
What minerals are found with brianite?+
What kind of rock does brianite form in?+
What is brianite used for?+
Find brianite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
