Bradleyite is a rare phosphate-carbonate mineral primarily associated with the evaporite sequences of the Green River Formation. It typically occurs as small, pale, equant crystals or masses embedded within oil shale and trona beds, making it a prized acquisition for collectors of rare evaporite species.
Is this bradleyite?
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 bradleyite with a known reference. Bradleyite sits at Mohs 3.5, 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: white, gray, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: equant to tabular crystals, massive, granular.
Often confused with
Bradleyite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside bradleyite
Minerals reported to co-occur with bradleyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₃Mg(PO₄)(CO₃)
- Mohs hardness
- 3.5
- Density
- 2.720-2.734 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Equant to tabular crystals, massive, granular
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector, Scientific research
- Host rock
- A rare mineral in oil shale in the Green River formation
Where rockhounds find bradleyite
Classic worldwide localities
- John Hay, Jr. Well No.1, about 30 km west of Green River, and in the Westvaco mine, Green River, Sweetwater Co., Wyoming, USA
Field-hunting tip
Where it forms: A rare mineral in oil shale in the Green River formation. If you start seeing shortite, clay minerals, trona in float, you are in the right ground. Typical habit: equant to tabular crystals, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify bradleyite?+
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What rocks look like bradleyite?+
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Find bradleyite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
