Minyulite is a rare hydrated potassium aluminum phosphate typically found as radiating clusters of acicular or prismatic crystals. It is most famous for its occurrence in phosphate-rich nodules, where it forms delicate, often star-shaped, white to colorless sprays.
Is this minyulite?
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 minyulite with a known reference. Minyulite 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, silky in aggregates.
- 4Match the color rangeCompare against the expected color range: white, colorless, green, light green.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: crystalline, radial.
Often confused with
Minyulite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside minyulite
Minerals reported to co-occur with minyulite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KAl₂(PO₄)₂(OH,F)·4H₂O
- Mohs hardness
- 3.5
- Density
- 2.45 g/cm³
- Streak
- White
- Luster
- Vitreous, silky in aggregates
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Crystalline, radial
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In weathered glauconitic phosphatic ironstone (Australia)
Where rockhounds find minyulite
Classic worldwide localities
- Found near Cockalorum Wash, Nye Co., and at the Willard mine, Willard district, Pershing Co., Nevada, USA
- Ross Hannibal mine, Lawrence Co., South Dakota, USA
- Utahlite Hill, eight km northwest of Lucin, Box Elder Co., Utah, USA
- Minyulo Well, Dandarragan, Western Australia
- Wait’s quarry and Oliver’s quarry, near Noarlunga, 32 km south of Adelaide, Western Australia
- Moculta phosphate quarry, northeast of Angaston, and from the St. John’s quarry, seven km southeast of Kapunda, Mount Lofty Ranges, South Australia
Field-hunting tip
Where it forms: In weathered glauconitic phosphatic ironstone (Australia). If you start seeing dufrénite, apatite, fluellite in float, you are in the right ground. Typical habit: crystalline, radial. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify minyulite?+
Where is minyulite found?+
What rocks look like minyulite?+
What minerals are found with minyulite?+
What kind of rock does minyulite form in?+
What is minyulite used for?+
Find minyulite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
