Tamaite is a rare manganese-bearing member of the pumpellyite group, typically occurring as fine fibrous or radiating acicular clusters. It is primarily identified by its characteristic brownish color and its occurrence in metamorphosed manganese deposits.
Is this tamaite?
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 tamaite with a known reference. Tamaite sits at Mohs 6 — softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Tamaite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Tamaite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: brown, yellow-brown, orange-brown.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: fibrous aggregates, radial sprays.
Often found alongside tamaite
Minerals reported to co-occur with tamaite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₄Mn²⁺Al₂(Si₂O₇)(SiO₄)(OH)₃·H₂O
- Mohs hardness
- 6
- Density
- 3.37 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Monoclinic
- Crystal habit
- Fibrous Aggregates, Radial Sprays
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Manganese Ore Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find tamaite
Classic worldwide localities
- Noda-Tamagawa mine, Iwate Prefecture, Japan
Field-hunting tip
Look in manganese ore deposits country — that is the host setting where tamaite typically forms. If you start seeing rhodochrosite, braunite, hausmannite in float, you are in the right ground. Field specimens usually show a fibrous aggregates, radial sprays habit, so train your eye for that shape before scanning the outcrop.
Common questions
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Find tamaite on the map
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