Kasatkinite is an extremely rare barium-calcium borosilicate mineral found in alkaline igneous complexes. It typically presents as colorless to white platy crystals or radiating sprays within quartz-rich matrices.

Hardness

4-4.5

Mohs

Luster

Vitreous to silky

Streak

White

Transparency

Translucent to nearly opaque

mineralrare

Kasatkinite

Hardness: 4-4.5
Luster: Vitreous to silky
Streak: White
Transparency: Translucent to nearly opaque

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Is this kasatkinite?

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 kasatkinite with a known reference. Kasatkinite sits at Mohs 4-4.5, 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: colorless, snow-white aggregates.
5
Look at form & habit
Crystal system: monoclinic. Typical habit: platy crystals, radiating aggregates.

Often confused with

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

mineral

Stillwellite-(Ce)

Mohs ~6.5

How to tell apart: Stillwellite-(Ce) is the harder of the two (Mohs ~6.5 vs. 4-4.5); luster reads vitreous to silky on Kasatkinite and resinous on Stillwellite-(Ce).

How to tell apart: Barylite is the harder of the two (Mohs 7 vs. 4-4.5).

Compare →

Often found alongside kasatkinite

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

All properties

Chemical formula: Ba₂Ca₈B₅Si₈O₃₂(OH)₃·6H₂O
Mohs hardness: 4-4.5
Density: 2.95 g/cm³
Colors: ColorlessSnow-white aggregates
Streak: White
Luster: Vitreous to silky
Transparency: Translucent to nearly opaque
Crystal system: Monoclinic
Crystal habit: Platy crystals, radiating aggregates
Cleavage: None observed
Rarity: Rare
Uses: Collector
Host rock: Of hydrothermal origin in cavities in rhodingite

Where rockhounds find kasatkinite

Classic worldwide localities

Bazhenovskoe chrysotile-asbestos deposit (eastern part of the open pit Yuzhnyi), near Asbest, Middle Urals, Russia

Field-hunting tip

Where it forms: Of hydrothermal origin in cavities in rhodingite. If you start seeing prehnite, pectolite, calcite in float, you are in the right ground. Typical habit: platy crystals, radiating aggregates. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kasatkinite?+

Mohs hardness is 4-4.5. Luster: vitreous to silky. The streak is white. Common colors include colorless, snow-white aggregates.

Where is kasatkinite found?+

Notable localities include Bazhenovskoe chrysotile-asbestos deposit (eastern part of the open pit Yuzhnyi), near Asbest, Middle Urals, Russia.

What rocks look like kasatkinite?+

Kasatkinite is most often confused with Stillwellite-(Ce), Barylite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kasatkinite?+

Kasatkinite commonly co-occurs with Prehnite, Pectolite, Calcite, Clinochlore, Grossular, Diopside. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kasatkinite form in?+

Where it forms: Of hydrothermal origin in cavities in rhodingite. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kasatkinite used for?+

Kasatkinite is used in collector.

Find kasatkinite on the map

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