Ilirneyite is a rare magnesium zinc manganese tellurite that forms interrupted earthy films. It occurs in the oxidation zone of sulfide-telluride-bearing quartz veins in cracks and cavities. It was first described from the Sentyabr'skoe gold-silver deposit, Western Chukotka, North-Eastern Region, Russia.
Is this ilirneyite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch ilirneyite with a known reference. Ilirneyite sits at Mohs ~3, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: brown.
- 3Read the lusterHold the specimen under a strong light. Luster: adamantine to semi-metallic (crystals); silky (aggregates).
- 4Match the color rangeCompare against the expected color range: reddish brown, dark brownish red, brown.
- 5Look at form & habitCrystal system: hexagonal. Typical habit: interrupted earthy films.
Often confused with
Ilirneyite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Scheelite is the harder of the two (Mohs 4.5-5 vs. ~3); streak differs, so Ilirneyite leaves brown, Scheelite leaves white; luster reads adamantine to semi-metallic (crystals); silky (aggregates) on Ilirneyite and vitreous to adamantine on Scheelite.
How to tell apart: Wolframite is the harder of the two (Mohs 4.5 vs. ~3); streak differs, so Ilirneyite leaves brown, Wolframite leaves reddish brown; luster reads adamantine to semi-metallic (crystals); silky (aggregates) on Ilirneyite and submetallic on Wolframite.
Often found alongside ilirneyite
Minerals reported to co-occur with ilirneyite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₀.₅[ZnMn³⁺(TeO₃)₃]·4.5H₂O
- Mohs hardness
- ~3
- Density
- 4.205 g/cm³
- Colors
- Streak
- Brown
- Luster
- Adamantine to semi-metallic (crystals); silky (aggregates)
- Transparency
- Transparent to translucent
- Crystal system
- Hexagonal
- Crystal habit
- Interrupted earthy films
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In the oxidation zone of sulfide-telluride-bearing quartz veins in cracks and cavities
Where rockhounds find ilirneyite
Classic worldwide localities
- Sentyabr’skoe gold-silver deposit, Ilirney ore district, 110 km east southeast of Bilibino, Western Chukotka, North-Eastern Region, Russia
Field-hunting tip
Where it forms: In the oxidation zone of sulfide-telluride-bearing quartz veins in cracks and cavities. If you start seeing gypsum, malachite, azurite in float, you are in the right ground. Typical habit: interrupted earthy films. Train your eye for that shape before scanning the outcrop.
Common questions
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Find ilirneyite on the map
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