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.

Hardness

6-7

Mohs

Luster

Vitreous

Streak

White

Transparency

Translucent

mineralrarePyroxene Group family

Kushiroite

Hardness: 6-7
Luster: Vitreous
Streak: White
Transparency: Translucent

No image

Is this kushiroite?

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 kushiroite with a known reference. Kushiroite sits at Mohs 6-7 — softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Kushiroite leaves a white streak.
3
Read the luster
Hold the specimen under a strong light. Kushiroite typically shows a vitreous luster.
4
Match the color range
Compare against the expected color range: green, dark green, black, brownish.
5
Look at form & habit
Crystal 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.

How to tell apart: Streak differs — Kushiroite leaves white, Hedenbergite leaves white to pale green; luster reads vitreous on Kushiroite and vitreous to resinous on Hedenbergite.

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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: 3.5-3.6 g/cm³
Colors: Green Dark Green Black Brownish
Streak: White
Luster: Vitreous
Transparency: Translucent
Crystal system: Monoclinic
Crystal habit: Prismatic Crystals, Anhedral Grains
Cleavage: Good in Two Directions
Rarity: Rare
Uses: Collector
Host rock: Metamorphic Rocks, Meteorites
Typical price: $50-500 depending on specimen size

Where rockhounds find kushiroite

Classic worldwide localities

Kushiro, Hokkaido, Japan
various meteorite impact sites

Field-hunting tip

Look in metamorphic rocks, meteorites country — that is the host setting where kushiroite typically forms. If you start seeing olivine, plagioclase, spinel in float, you are in the right ground. Field specimens usually show a prismatic crystals, anhedral grains habit, so train your eye for that shape before scanning the outcrop.

Common questions

How do you identify kushiroite?+

Mohs hardness is 6-7. It typically shows a vitreous luster. The streak is white. Common colors include green, dark green, black, brownish.

Where is kushiroite found?+

Notable localities include Kushiro, Hokkaido, Japan; various meteorite impact sites.

How much is kushiroite worth?+

Typical asking prices fall in the range of $50-500 depending on specimen size. Quality, size, and provenance can move individual specimens well outside that range.

What rocks look like kushiroite?+

Kushiroite is most often confused with Diopside, Esseneite, Hedenbergite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with kushiroite?+

Kushiroite commonly co-occurs with Olivine, Plagioclase, Spinel. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does kushiroite form in?+

Kushiroite typically forms in metamorphic rocks, meteorites. Working float back to the host body is the standard way to chase a fresh occurrence.

What is kushiroite used for?+

Kushiroite is used in collector.

Find kushiroite on the map

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