Clinoenstatite is the monoclinic high-temperature polymorph of enstatite, often found in meteorites and specialized geological environments. It typically occurs as white or colorless prismatic crystals or granular masses and is notoriously difficult to distinguish from its orthorhombic counterpart, enstatite, without X-ray diffraction. Collectors value it primarily for its scientific significance as a component of extraterrestrial and mantle-derived materials.
Is this clinoenstatite?
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 clinoenstatite with a known reference. Clinoenstatite 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. Streak: greenish gray.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous to pearly.
- 4Match the color rangeCompare against the expected color range: colorless, green, greenish yellow, yellow brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: columnar, crystalline, granular.
Often confused with
Clinoenstatite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Clinoenstatite leaves greenish gray, Enstatite leaves white to grayish.
How to tell apart: Forsterite is the harder of the two (Mohs 7 vs. 5-6); streak differs, so Clinoenstatite leaves greenish gray, Forsterite leaves white.
How to tell apart: Streak differs, so Clinoenstatite leaves greenish gray, Diopside leaves white, gray, gray-green.
Often found alongside clinoenstatite
Minerals reported to co-occur with clinoenstatite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- MgSiO₃
- Mohs hardness
- 5-6
- Density
- 3.2-3.6 g/cm³
- Streak
- Greenish gray
- Luster
- Vitreous to pearly
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Columnar, crystalline, granular
- Cleavage
- Good on {110}, (110) ^ (110) ~91°
- Rarity
- Rare
- Uses
- Collector, Research
- Host rock
- As phenocrysts, likely inverted from protoenstatite, in high-magnesium nonfeldspathic andesites
Where rockhounds find clinoenstatite
Classic worldwide localities
- Mt. Stuart batholith, central Cascade Mountains, Washington, USA
- Cape Vogel, Papua New Guinea, and on the inner slope of the Mariana trench
- Chichijima and Mukojima, Ogasawara (Bonin) Islands, Japan
- Népoui, New Caledonia
Field-hunting tip
Where it forms: As phenocrysts, likely inverted from protoenstatite, in high-magnesium nonfeldspathic andesites. If you start seeing diopside, enstatite, chromite in float, you are in the right ground. Typical habit: columnar, crystalline, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify clinoenstatite?+
Where is clinoenstatite found?+
What rocks look like clinoenstatite?+
What minerals are found with clinoenstatite?+
What kind of rock does clinoenstatite form in?+
What is clinoenstatite used for?+
Find clinoenstatite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
