Okhotskite is a rare member of the pumpellyite group, distinct for its high manganese content which gives it a characteristic reddish-brown color. It is typically found in manganese-rich metamorphic environments and forms small prismatic or acicular crystals.
Is this okhotskite?
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 okhotskite with a known reference. Okhotskite 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. Okhotskite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Okhotskite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: red, brownish-red.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: prismatic to acicular crystals, fibrous aggregates.
Often confused with
Okhotskite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside okhotskite
Minerals reported to co-occur with okhotskite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄Mn²⁺Al₂Mn³⁺(Si₂O₇)(SiO₄)(OH)₃
- Mohs hardness
- 5-6
- Density
- 3.3-3.5 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Prismatic to Acicular Crystals, Fibrous Aggregates
- Cleavage
- Good in One Direction
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Manganese-rich Metamorphic Rocks
- Typical price
- $50-300 per specimen
Where rockhounds find okhotskite
Classic worldwide localities
- Okhotsk Sea region, Japan
- Hokkaido, Japan
Field-hunting tip
Look in manganese-rich metamorphic rocks country — that is the host setting where okhotskite typically forms. If you start seeing quartz, hematite, albite in float, you are in the right ground. Field specimens usually show a prismatic to acicular crystals, fibrous aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find okhotskite on the map
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