Schlüterite-(Y) is a rare yttrium aluminium silicate of the Eifel volcanic region, Germany. It is named for the German mineralogist Jochen Schlüter.

Hardness

5.5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareTundrite Group family

Schlüterite-(Y)

Schlüterite-(Y) is a rare yttrium aluminium silicate of the Eifel volcanic region, Germany. It is named for the German mineralogist Jochen Schlüter.

Hardness: 5.5-6
Luster: Vitreous
Streak: White
Transparency: Transparent

No image

Is this schlüterite-(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 schlüterite-(y) with a known reference. Schlüterite-(Y) sits at Mohs 5.5-6, 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: pale pink.
5
Look at form & habit
Crystal system: monoclinic.

Often confused with

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

mineral

Tundrite-(Ce)

Mohs ~3

How to tell apart: Schlüterite-(Y) is noticeably harder (Mohs 5.5-6 vs. ~3); streak differs, so Schlüterite-(Y) leaves white, Tundrite-(Ce) leaves yellowish gray to white.

How to tell apart: Schlüterite-(Y) is noticeably harder (Mohs 5.5-6 vs. 3).

Compare →

Often found alongside schlüterite-(y)

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

All properties

Chemical formula: (Y,REE)₂AlSi₂O₇(OH)₂F
Mohs hardness: 5.5-6
Density: 4.644 g/cm³
Colors: Pale pink
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Monoclinic
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: As inclusions in yttrium-rich fluorite in a NYF-type quartz-microcline pegmatite

Where rockhounds find schlüterite-(y)

Classic worldwide localities

Stetind pegmatite, Tysfjord, Nordland, Norway

Field-hunting tip

Where it forms: As inclusions in yttrium-rich fluorite in a NYF-type quartz-microcline pegmatite. If you start seeing fluorite, bastnäsite-, yttrian fluorite in float, you are in the right ground.

Common questions

How do you identify schlüterite-(y)?+

Mohs hardness is 5.5-6. Luster: vitreous. The streak is white. Common colors include pale pink.

Where is schlüterite-(y) found?+

Notable localities include Stetind pegmatite, Tysfjord, Nordland, Norway.

What rocks look like schlüterite-(y)?+

Schlüterite-(Y) is most often confused with Tundrite-(Ce), Tundrite-(Nd). A quick hardness test and a streak check separate the look-alikes faster than color alone.

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

Schlüterite-(Y) commonly co-occurs with Fluorite, Bastnäsite-, Yttrian fluorite, Fluorthalénite-, Hematite, Hundholmenite-. Spotting any of these in float or country rock is a useful trip signal.

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

Where it forms: As inclusions in yttrium-rich fluorite in a NYF-type quartz-microcline pegmatite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is schlüterite-(y) used for?+

Schlüterite-(Y) is used in collector.

Find schlüterite-(y) on the map

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