Peatite-(Y) is an extremely rare yttrium carbonate mineral typically found as an alteration product of other yttrium-bearing minerals. Collectors usually identify it by its dull, earthy, or fibrous white crusts forming in cavities or on weathered pegmatite minerals.

Hardness

3-4

Mohs

Luster

Dull

Streak

White

Transparency

Opaque

mineralrareTengerite Group family

Peatite-(Y)

Hardness: 3-4
Luster: Dull
Streak: White
Transparency: Opaque

Is this peatite-(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 peatite-(y) with a known reference. Peatite-(Y) sits at Mohs 3-4 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Peatite-(Y) leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Peatite-(Y) typically shows a dull luster.
4
Match the color range
Compare against the expected color range: white, yellowish-white, grayish-white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: fibrous, earthy, massive.

Often confused with

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

How to tell apart: Luster reads dull on Peatite-(Y) and vitreous on Calcite.

How to tell apart: Luster reads dull on Peatite-(Y) and pearly on Hydromagnesite.

Compare →

Often found alongside peatite-(y)

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

All properties

Chemical formula: Y₂(CO₃)₃·nH₂O
Mohs hardness: 3-4
Density: 3.3-3.6 g/cm³
Colors: White Yellowish-white Grayish-white
Streak: White
Luster: Dull
Transparency: Opaque
Crystal system: Orthorhombic
Crystal habit: Fibrous, Earthy, Massive
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: Granite Pegmatites
Typical price: $50-300 per specimen

Where rockhounds find peatite-(y)

Classic worldwide localities

Sweden
USA
Norway
Canada

Field-hunting tip

Look in granite pegmatites country — that is the host setting where peatite-(y) typically forms. If you start seeing allanite, gadolinite, fluorite in float, you are in the right ground. Field specimens usually show a fibrous, earthy, massive habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify peatite-(y)?+

Mohs hardness is 3-4. It typically shows a dull luster. The streak is white. Common colors include white, yellowish-white, grayish-white.

Where is peatite-(y) found?+

Notable localities include Sweden; USA; Norway; Canada.

How much is peatite-(y) worth?+

Typical asking prices fall in the range of $50-300 per specimen. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like peatite-(y)?+

Peatite-(Y) is most often confused with Tengerite-(Y), Calcite, Hydromagnesite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

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

Peatite-(Y) commonly co-occurs with Allanite, Gadolinite, Fluorite, Quartz. Spotting any of these in float or country rock is a useful trip signal.

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

Peatite-(Y) typically forms in granite pegmatites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is peatite-(y) used for?+

Peatite-(Y) is used in collector.

Find peatite-(y) on the map

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