Pyroxene is a major group of rock-forming silicate minerals found extensively in igneous and metamorphic environments. They are distinguished from similar amphiboles by their characteristic two cleavage planes that intersect at nearly 90 degrees.
Is this pyroxene?
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 pyroxene with a known reference. Pyroxene sits at Mohs 5-6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Pyroxene leaves a white to grey streak.
- 3Read the lusterHold the specimen under a strong light. Pyroxene typically shows a vitreous to dull luster.
- 4Match the color rangeCompare against the expected color range: black, dark green, brown, gray.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic crystals, granular, massive.
Often confused with
Pyroxene vs. its common look-alikes — and how to tell them apart in the field.
How to tell apart: Streak differs — Pyroxene leaves white to grey, Amphibole leaves white to gray; luster reads vitreous to dull on Pyroxene and vitreous to silky on Amphibole.
How to tell apart: Streak differs — Pyroxene leaves white to grey, Epidote leaves white; luster reads vitreous to dull on Pyroxene and vitreous on Epidote.
How to tell apart: Tourmaline is the harder of the two (Mohs 7-7.5 vs. 5-6); streak differs — Pyroxene leaves white to grey, Tourmaline leaves white; luster reads vitreous to dull on Pyroxene and vitreous on Tourmaline.
Often found alongside pyroxene
Minerals reported to co-occur with pyroxene. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- XY(Si,Al)₂O₆
- Mohs hardness
- 5-6
- Density
- 3.2-3.6 g/cm³
- Colors
- Streak
- White to Grey
- Luster
- Vitreous to Dull
- Transparency
- Opaque
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic Crystals, Granular, Massive
- Cleavage
- Good in 2 Directions At Nearly 90 Degrees
- Rarity
- Common
- Uses
- Collector, Petrology Study
- Host rock
- Igneous and Metamorphic Rocks
- Typical price
- $5-30 for typical specimens
Where rockhounds find pyroxene
1 mapped spotsClassic worldwide localities
- Italy
- Germany
- Canada
- USA
- Norway
Field-hunting tip
Look in igneous and metamorphic rocks country — that is the host setting where pyroxene typically forms. If you start seeing plagioclase, olivine, magnetite in float, you are in the right ground. Field specimens usually show a prismatic crystals, granular, massive habit, so train your eye for that shape before scanning the outcrop. In the U.S., the densest reported localities are in New York — start trip planning there.
Common questions
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Find pyroxene on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
