Donpeacorite is a rare manganese-rich member of the orthopyroxene group, structurally distinct from its monoclinic counterparts. It is primarily found in metamorphosed manganese deposits where it forms yellowish-brown prismatic crystals or granular aggregates. Collectors usually seek specimens from historic Swedish manganese mines or the famous Franklin locality.
Is this donpeacorite?
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 donpeacorite with a known reference. Donpeacorite 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: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: yellow orange.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: prismatic, massive, granular.
Often confused with
Donpeacorite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Streak differs, so Donpeacorite leaves white, Ferrosilite leaves pale brownish gray.
How to tell apart: Streak differs, so Donpeacorite leaves white, Clinoenstatite leaves greenish gray.
Often found alongside donpeacorite
Minerals reported to co-occur with donpeacorite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- (Mn,Mg)MgSi₂O₆
- Mohs hardness
- 5-6
- Density
- 3.36 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Orthorhombic
- Crystal habit
- Prismatic, massive, granular
- Cleavage
- Perfect on {110}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In manganese-rich siliceous marbles metamorphosed to the upper amphibolite facies
Where rockhounds find donpeacorite
Classic worldwide localities
- Balmat No. 4 mine, Balmat, St. Lawrence Co., New York, USA
Field-hunting tip
Where it forms: In manganese-rich siliceous marbles metamorphosed to the upper amphibolite facies. If you start seeing tirodite, tourmaline, ferrian braunite in float, you are in the right ground. Typical habit: prismatic, massive, granular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify donpeacorite?+
Where is donpeacorite found?+
What rocks look like donpeacorite?+
What minerals are found with donpeacorite?+
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Find donpeacorite on the map
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