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 — that is 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.