Protoenstatite is a high-temperature polymorph of magnesium silicate that is notably unstable at surface conditions. It is primarily identified in meteoritic samples or high-temperature synthetic experiments rather than typical terrestrial geological settings. Collectors usually find it represented in specialized petrological research collections or as minute inclusions within extraterrestrial matter.
Is this protoenstatite?
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 protoenstatite with a known reference. Protoenstatite sits at Mohs 5.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Protoenstatite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Protoenstatite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: colorless, white, gray, greenish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: rarely found as distinct crystals; typically identified via micro-inclusions or synthetic conditions.
Often confused with
Protoenstatite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside protoenstatite
Minerals reported to co-occur with protoenstatite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Mg₂Si₂O₆
- Mohs hardness
- 5.5
- Density
- 3.19 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Rarely Found as Distinct Crystals; Typically Identified Via Micro-inclusions or Synthetic Conditions
- Cleavage
- Good
- Rarity
- Rare
- Uses
- Collector, Research
- Host rock
- Igneous
- Typical price
- $50-500 depending on specimen provenance and research quality
Where rockhounds find protoenstatite
Classic worldwide localities
- meteorites
- high-temperature volcanic environments
- synthetic laboratories
Field-hunting tip
Look in igneous country, the host setting where protoenstatite typically forms. If you start seeing olivine, diopside, plagioclase in float, you are in the right ground. Field specimens usually show a rarely found as distinct crystals; typically identified via micro-inclusions or synthetic conditions habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find protoenstatite on the map
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