Tanohataite is a rare lithium-sodium-manganese silicate first discovered in the Tanohata mine of Japan. It typically occurs as small tabular crystals associated with manganese ore minerals in skarn-like assemblages. Due to its extreme rarity and very limited occurrence, it is primarily of interest to systematic mineral collectors.
Is this tanohataite?
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 tanohataite with a known reference. Tanohataite sits at Mohs 5-5.5, 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, silky [aggregates].
- 4Match the color rangeCompare against the expected color range: pinkish white, black with oxidation.
- 5Look at form & habitCrystal system: triclinic. Typical habit: tabular crystals.
Often confused with
Tanohataite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside tanohataite
Minerals reported to co-occur with tanohataite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- LiMn₂Si₃O₈(OH)
- Mohs hardness
- 5-5.5
- Density
- 3.33 g/cm³
- Colors
- Pinkish whiteBlack with oxidation
- Streak
- White
- Luster
- Vitreous, silky [aggregates]
- Transparency
- Transparent
- Crystal system
- Triclinic
- Crystal habit
- Tabular crystals
- Cleavage
- Perfect on {001} and {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In lens-like veins in a sediment-hosted Mn-ore deposit in contact metamorphic rocks near a granodiorite intrusion
Where rockhounds find tanohataite
Classic worldwide localities
- Matsumaezawa pit, Tanohata mine, Tanohata Village, Iwate Prefecture, Japan (type locality)
Field-hunting tip
Where it forms: In lens-like veins in a sediment-hosted Mn-ore deposit in contact metamorphic rocks near a granodiorite intrusion. If you start seeing quartz, aegirine, mn-arfvedsonite in float, you are in the right ground. Typical habit: tabular crystals. Train your eye for that shape before scanning the outcrop.
Common questions
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Find tanohataite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
