Watatsumiite is a rare manganese-bearing silicate mineral belonging to the pectolite group. It is typically found in manganese ore deposits as radiating, fibrous, or acicular aggregates with a distinct reddish-purple hue.
Is this watatsumiite?
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 watatsumiite with a known reference. Watatsumiite 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. Watatsumiite leaves a white streak.
- 3Read the lusterHold the specimen under a strong light. Watatsumiite typically shows a vitreous luster.
- 4Match the color rangeCompare against the expected color range: purple, reddish-purple.
- 5Look at form & habitCrystal system: triclinic. Typical habit: fibrous, acicular, radiating aggregates.
Often confused with
Watatsumiite vs. its common look-alikes — and how to tell them apart in the field.
Often found alongside watatsumiite
Minerals reported to co-occur with watatsumiite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Na₂Mn₂TiSi₄O₁₂O₂
- Mohs hardness
- 5.5
- Density
- 3.32 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Translucent
- Crystal system
- Triclinic
- Crystal habit
- Fibrous, Acicular, Radiating Aggregates
- Cleavage
- Perfect On {100} and {010}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- Manganese-rich Hydrothermal Deposits
- Typical price
- $50-300 per specimen
Where rockhounds find watatsumiite
Classic worldwide localities
- Tanohata mine, Iwate Prefecture, Japan
Field-hunting tip
Look in manganese-rich hydrothermal deposits country — that is the host setting where watatsumiite typically forms. If you start seeing quartz, albite, mangan-pyrosmalite in float, you are in the right ground. Field specimens usually show a fibrous, acicular, radiating aggregates habit, so train your eye for that shape before scanning the outcrop.
Common questions
How do you identify watatsumiite?+
Where is watatsumiite found?+
How much is watatsumiite worth?+
What rocks look like watatsumiite?+
What minerals are found with watatsumiite?+
What kind of rock does watatsumiite form in?+
What is watatsumiite used for?+
Find watatsumiite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
