Pilawite-(Y) is an exceptionally rare silicate mineral member of the gadolinite group, typically found in pegmatitic environments. Collectors should look for dark, heavy crystals often displaying metamict features due to natural radioactive decay.

Hardness

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrareGadolinite Group family

Pilawite-(Y)

Hardness: 5
Luster: Vitreous
Streak: White
Transparency: Translucent

No image

Is this pilawite-(y)?

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 pilawite-(y) with a known reference. Pilawite-(Y) sits at Mohs 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: white.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: prismatic crystals, massive.

Often confused with

Pilawite-(Y) vs. its common look-alikes, and how to tell them apart in the field.

mineral

Gadolinite-(Y)

Mohs 6.5-7

How to tell apart: Gadolinite-(Y) is the harder of the two (Mohs 6.5-7 vs. 5); streak differs, so Pilawite-(Y) leaves white, Gadolinite-(Y) leaves greenish gray.

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All properties

Chemical formula: Ca₂Y₂Al₄(SiO₄)₄O₂(OH)₂
Mohs hardness: 5
Density: 4.007 g/cm³
Colors: White
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Prismatic crystals, massive
Cleavage: None observed
Rarity: Rare
Uses: Collector
Host rock: Within the blocky feldspar zone of a weakly zoned and weakly fractionated NYF-affiliated granitic pegmatite dike

Where rockhounds find pilawite-(y)

Classic worldwide localities

Poland
Russia
Sweden

Field-hunting tip

Where it forms: Within the blocky feldspar zone of a weakly zoned and weakly fractionated NYF-affiliated granitic pegmatite dike. If you start seeing keiviite-, gadolinite-, hingganite- in float, you are in the right ground. Typical habit: prismatic crystals, massive. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify pilawite-(y)?+

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

Where is pilawite-(y) found?+

Notable localities include Poland; Russia; Sweden.

Is pilawite-(y) safe to handle?+

Pilawite-(Y) contains trace uranium or thorium. Contains minor amounts of radioactive elements like thorium or uranium; handle with care and wash hands after handling.

What rocks look like pilawite-(y)?+

Pilawite-(Y) is most often confused with Gadolinite-(Y). A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with pilawite-(y)?+

Pilawite-(Y) commonly co-occurs with Keiviite-, Gadolinite-, Hingganite-, Hellandite-. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does pilawite-(y) form in?+

Where it forms: Within the blocky feldspar zone of a weakly zoned and weakly fractionated NYF-affiliated granitic pegmatite dike. Working float back to the host body is the standard way to chase a fresh occurrence.

What is pilawite-(y) used for?+

Pilawite-(Y) is used in collector.

Find pilawite-(y) on the map

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