Kushiroite is a very rare calcium-aluminum pyroxene that was first identified in terrestrial rocks from the Kushiro region of Japan. It is typically found as small, dark-colored grains in high-temperature metamorphic environments or in certain chondritic meteorites.
Is this kushiroite?
3-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 kushiroite with a known reference. Kushiroite sits at Mohs 6-7, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, anhedral grains.
Often confused with
Kushiroite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside kushiroite
Minerals reported to co-occur with kushiroite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- CaAlAlSiO₆
- Mohs hardness
- 6-7
- Density
- 3.44 g/cm³
- Streak
- White
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic crystals, anhedral grains
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In a refractory inclusion in a CH group carbonaceous chondrite meteorite, perhaps formed by metastable crystallization from refractory melts in the solar nebula
Where rockhounds find kushiroite
Classic worldwide localities
- CH3 chondrite ALH85085 (type locality)
Field-hunting tip
Where it forms: In a refractory inclusion in a CH group carbonaceous chondrite meteorite, perhaps formed by metastable crystallization from refractory melts in the solar nebula. If you start seeing grossite, addibischoffite, hibonite in float, you are in the right ground. Typical habit: prismatic crystals, anhedral grains. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify kushiroite?+
Where is kushiroite found?+
What rocks look like kushiroite?+
What minerals are found with kushiroite?+
What kind of rock does kushiroite form in?+
What is kushiroite used for?+
Find kushiroite on the map
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