Irinarassite is a very rare tin-bearing garnet species discovered in the Wiluy River basin of Russia. It typically occurs as small dodecahedral crystals within skarn deposits and is highly prized by advanced mineral collectors for its unique composition.

Hardness

6-7

Mohs

Streak

Ashy yellow

Transparency

Transparent

mineralrareGarnet Group family

Irinarassite

Hardness: 6-7
Streak: Ashy yellow
Transparency: Transparent

No image

Is this irinarassite?

4-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 irinarassite with a known reference. Irinarassite sits at Mohs 6-7, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: ashy yellow.
3
Match the color range
Compare against the expected color range: yellow, pale brown.
4
Look at form & habit
Crystal system: cubic. Typical habit: dodecahedral crystals.

Often confused with

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

mineral

Andradite

Mohs 6.5-7

How to tell apart: Streak differs, so Irinarassite leaves ashy yellow, Andradite leaves white.

How to tell apart: Streak differs, so Irinarassite leaves ashy yellow, Grossular leaves white.

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Often found alongside irinarassite

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

All properties

Chemical formula: Ca₃Sn₂(Al₂Si)O₁₂
Mohs hardness: 6-7
Density: 4.301 g/cm³
Colors: Yellow Pale brown
Streak: Ashy yellow
Transparency: Transparent
Crystal system: Cubic
Crystal habit: Dodecahedral crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In a metasomatically-altered (sanidinite facies), carbonate-silicate xenolith in ignimbrite

Where rockhounds find irinarassite

Classic worldwide localities

Sakha Republic, Russia

Field-hunting tip

Where it forms: In a metasomatically-altered (sanidinite facies), carbonate-silicate xenolith in ignimbrite. If you start seeing lakargiite, tazheranite, baddeleyite in float, you are in the right ground. Typical habit: dodecahedral crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify irinarassite?+

Mohs hardness is 6-7. The streak is ashy yellow. Common colors include yellow, pale brown.

Where is irinarassite found?+

Notable localities include Sakha Republic, Russia.

What rocks look like irinarassite?+

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

What minerals are found with irinarassite?+

Irinarassite commonly co-occurs with Lakargiite, Tazheranite, Baddeleyite, Baghdadite, Magnesioferrite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does irinarassite form in?+

Where it forms: In a metasomatically-altered (sanidinite facies), carbonate-silicate xenolith in ignimbrite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is irinarassite used for?+

Irinarassite is used in collector.

Find irinarassite on the map

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