Rusinovite is an extremely rare calcium silicate chloride mineral discovered in the Chegem volcanic caldera in Russia. It typically occurs as small tabular crystals within high-temperature skarn environments associated with carbonate-rich volcanic xenoliths.

Hardness

4-5

Mohs

Luster

Vitreous to silky

Streak

White

Transparency

Transparent

mineralrare

Rusinovite

Hardness: 4-5
Luster: Vitreous to silky
Streak: White
Transparency: Transparent

No image

Is this rusinovite?

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 rusinovite with a known reference. Rusinovite sits at Mohs 4-5, 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 to silky.
4
Match the color range
Compare against the expected color range: white.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: tabular crystals.

Often confused with

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

How to tell apart: Larnite is the harder of the two (Mohs 6 vs. 4-5).

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Often found alongside rusinovite

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

All properties

Chemical formula: Ca₁₀(Si₂O₇)₃Cl₂
Mohs hardness: 4-5
Density: 2.93 g/cm³
Colors: White
Streak: White
Luster: Vitreous to silky
Transparency: Transparent
Crystal system: Orthorhombic
Crystal habit: Tabular crystals
Cleavage: Good on (010)
Rarity: Rare
Uses: Collector
Host rock: In a thermally altered (sanidinite facies) carbonate-silicate xenolith about 10 m in size enclosed in ignimbrite

Where rockhounds find rusinovite

Classic worldwide localities

Upper Chegem caldera, near Mt. Lakargi, Kabardino-Balkaria, Northern Caucasus, Russia

Field-hunting tip

Where it forms: In a thermally altered (sanidinite facies) carbonate-silicate xenolith about 10 m in size enclosed in ignimbrite. If you start seeing wadalite, wollastonite, trabzonite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify rusinovite?+

Mohs hardness is 4-5. Luster: vitreous to silky. The streak is white. Common colors include white.

Where is rusinovite found?+

Notable localities include Upper Chegem caldera, near Mt. Lakargi, Kabardino-Balkaria, Northern Caucasus, Russia.

What rocks look like rusinovite?+

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

What minerals are found with rusinovite?+

Rusinovite commonly co-occurs with Wadalite, Wollastonite, Trabzonite, Rankinite, Larnite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does rusinovite form in?+

Where it forms: In a thermally altered (sanidinite facies) carbonate-silicate xenolith about 10 m in size enclosed in ignimbrite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is rusinovite used for?+

Rusinovite is used in collector.

Find rusinovite on the map

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