Wilancookite is a rare phosphate mineral found in granitic pegmatites. It typically occurs as small, colorless to white equant crystals associated with beryllium and lithium-rich environments.

Hardness

4-5

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrare

Wilancookite

Wilancookite is a rare phosphate mineral found in granitic pegmatites. It typically occurs as small, colorless to white equant crystals associated with beryllium and lithium-rich environments.

Hardness: 4-5
Luster: Vitreous
Streak: White
Transparency: Transparent

Is this wilancookite?

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 wilancookite with a known reference. Wilancookite sits at Mohs 4-5, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: white.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous.
4
Match the color range
Compare against the expected color range: colorless.
5
Look at form & habit
Crystal system: cubic. Typical habit: equant crystals.

Often confused with

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

Often found alongside wilancookite

Minerals reported to co-occur with wilancookite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: (Ba₅Li₂□)Ba₆Be₂₄P₂₄O₉₆·26H₂O
Mohs hardness: 4-5
Density: 3.05 g/cm³
Colors: Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Equant crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: A secondary mineral in phosphate nodules near the quartz core of a complex granitic pegmatite, formed during late stages by reaction between montebrasite and beryl

Where rockhounds find wilancookite

Classic worldwide localities

Lavra Ponte do Piauí pegmatite, Itinga, Jequitinhonha, Minas Gerais, Brazil

Field-hunting tip

Where it forms: A secondary mineral in phosphate nodules near the quartz core of a complex granitic pegmatite, formed during late stages by reaction between montebrasite and beryl. If you start seeing fluorapatite, childrenite, eosphorite in float, you are in the right ground. Typical habit: equant crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify wilancookite?+

Mohs hardness is 4-5. Luster: vitreous. The streak is white. Common colors include colorless.

Where is wilancookite found?+

Notable localities include Lavra Ponte do Piauí pegmatite, Itinga, Jequitinhonha, Minas Gerais, Brazil.

Is wilancookite safe to handle?+

Wilancookite contains beryllium. Wash your hands afterwards, never grind or breathe the dust, and store it apart from specimens you handle often.

What rocks look like wilancookite?+

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

What minerals are found with wilancookite?+

Wilancookite commonly co-occurs with Fluorapatite, Childrenite, Eosphorite, Zanazziite, Greifenstenite, Guimarãesite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does wilancookite form in?+

Where it forms: A secondary mineral in phosphate nodules near the quartz core of a complex granitic pegmatite, formed during late stages by reaction between montebrasite and beryl. Working float back to the host body is the standard way to chase a fresh occurrence.

What is wilancookite used for?+

Wilancookite is used in collector.

Find wilancookite on the map

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