Cryobostryxite is a rare potassium zinc oxide that forms colorless prismatic to acicular crystals. Associated minerals include gypsum, ralstonite and opal. It was first described from the First scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia.
Is this cryobostryxite?
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 cryobostryxite with a known reference. Cryobostryxite sits at Mohs ~2, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic to acicular crystals.
Often confused with
Cryobostryxite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside cryobostryxite
Minerals reported to co-occur with cryobostryxite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- KZnCl₃·2H₂O
- Mohs hardness
- ~2
- Density
- 2.30 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic to acicular crystals
- Cleavage
- None
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Formed as sublimates on basaltic scoria around active volcanic fumaroles and with involvement of meteoric water
Where rockhounds find cryobostryxite
Classic worldwide localities
- First scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia
Field-hunting tip
Where it forms: Formed as sublimates on basaltic scoria around active volcanic fumaroles and with involvement of meteoric water. If you start seeing gypsum, ralstonite, opal in float, you are in the right ground. Typical habit: prismatic to acicular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify cryobostryxite?+
Where is cryobostryxite found?+
What rocks look like cryobostryxite?+
What minerals are found with cryobostryxite?+
What kind of rock does cryobostryxite form in?+
What is cryobostryxite used for?+
Find cryobostryxite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
