Shibkovite is a rare potassium calcium zinc oxide that forms white to colorless equant grains. It occurs in coarse-grained microcline-quartz rocks in glacial moraine. It was first described from the moraine of the Dara-i-Pioz glacier, northern Tajikistan.

Hardness

5.5-6

Mohs

Luster

Vitreous

Streak

White

Transparency

Transparent

mineralrareMilarite-Osumilite Group family

Shibkovite

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

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Is this shibkovite?

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 shibkovite with a known reference. Shibkovite 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: white, colorless.
5
Look at form & habit
Crystal system: hexagonal. Typical habit: microscopic crystals.

Often confused with

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

How to tell apart: Streak differs, so Shibkovite leaves white, Osumilite leaves blue-gray.

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Often found alongside shibkovite

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

All properties

Chemical formula: K₂Ca₂(Zn₃Si₁₂)O₃₀
Mohs hardness: 5.5-6
Density: 2.89 g/cm³
Colors: White Colorless
Streak: White
Luster: Vitreous
Transparency: Transparent
Crystal system: Hexagonal
Crystal habit: Microscopic crystals
Cleavage: None
Rarity: Rare
Uses: Collector
Host rock: In coarse-grained microcline-quartz rocks in glacial moraine

Where rockhounds find shibkovite

Classic worldwide localities

Dara-i-Pioz glacier, Garmsky District, northern Tajikistan (type locality)

Field-hunting tip

Where it forms: In coarse-grained microcline-quartz rocks in glacial moraine. If you start seeing reedmergnerite, aegirine, polylithionite in float, you are in the right ground. Typical habit: microscopic crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify shibkovite?+

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

Where is shibkovite found?+

Notable localities include Dara-i-Pioz glacier, Garmsky District, northern Tajikistan (type locality).

What rocks look like shibkovite?+

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

What minerals are found with shibkovite?+

Shibkovite commonly co-occurs with Reedmergnerite, Aegirine, Polylithionite, Sogdianite, Albite, Pyrochlore. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does shibkovite form in?+

Where it forms: In coarse-grained microcline-quartz rocks in glacial moraine. Working float back to the host body is the standard way to chase a fresh occurrence.

What is shibkovite used for?+

Shibkovite is used in collector.

Find shibkovite on the map

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