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.

Hardness

3.5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Minyulite

Hardness: 3.5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this minyulite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch minyulite with a known reference. Minyulite sits at Mohs 3.5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Minyulite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Minyulite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: white, colorless, pale yellow.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: acicular or radiating aggregates, prismatic crystals.

Often confused with

Minyulite vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Luster reads vitreous on Minyulite and waxy on Variscite.

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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: 2.44 g/cm³
Colors: White Colorless Pale Yellow
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Acicular or Radiating Aggregates, Prismatic Crystals
Cleavage: Distinct On {110}
Rarity: Rare
Uses: Collector
Host rock: Phosphate-rich Sedimentary Environments, Hydrothermal Veins
Typical price: $20-100 per specimen depending on crystal size

Where rockhounds find minyulite

Classic worldwide localities

Minyulo Well, Western Australia
Långban, Sweden
Centerville, South Dakota
Near Boron, California

Field-hunting tip

Look in phosphate-rich sedimentary environments, hydrothermal veins country, the host setting where minyulite typically forms. If you start seeing wavellite, variscite, crandallite in float, you are in the right ground. Field specimens usually show a acicular or radiating aggregates, prismatic crystals habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify minyulite?+

Mohs hardness is 3.5. It typically shows a vitreous luster. The streak is white. Common colors include white, colorless, pale yellow.

Where is minyulite found?+

Notable localities include Minyulo Well, Western Australia; Långban, Sweden; Centerville, South Dakota; Near Boron, California.

How much is minyulite worth?+

Typical asking prices fall in the range of $20-100 per specimen depending on crystal size. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like minyulite?+

Minyulite is most often confused with Wavellite, Variscite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with minyulite?+

Minyulite commonly co-occurs with wavellite, variscite, crandallite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does minyulite form in?+

Minyulite typically forms in phosphate-rich sedimentary environments, hydrothermal veins. Working float back to the host body is the standard way to chase a fresh occurrence.

What is minyulite used for?+

Minyulite is used in collector.

Find minyulite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.