Clinotobermorite is a rare calcium silicate hydrate mineral found primarily in metamorphic skarn environments. It forms as thin, platy or fibrous aggregates and is often distinguished from standard tobermorite by its monoclinic crystal structure. Collectors typically find it as an accessory mineral in complex calcium-silicate assemblages formed through contact metamorphism.
Is this clinotobermorite?
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 clinotobermorite with a known reference. Clinotobermorite sits at Mohs 4.5, 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.
- 4Match the color rangeCompare against the expected color range: white, colorless.
- 5Look at form & habitCrystal system: monoclinic. Typical habit: acicular, platy, tabular.
Often confused with
Clinotobermorite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside clinotobermorite
Minerals reported to co-occur with clinotobermorite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Ca₅Si₆(O,OH)₁₈·5H₂O
- Mohs hardness
- 4.5
- Density
- 2.58 g/cm³
- Streak
- White
- Luster
- Vitreous
- Transparency
- Semitransparent
- Crystal system
- Monoclinic
- Crystal habit
- Acicular, platy, tabular
- Cleavage
- Perfect on {001}, poor on {100}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In gehlenite-spurrite-bearing skarns
Where rockhounds find clinotobermorite
Classic worldwide localities
- Fuka, near Bicchu, Okayama Prefecture, Japan
- Wessels mine, Kalahari manganese field, South Africa
Field-hunting tip
Where it forms: In gehlenite-spurrite-bearing skarns. If you start seeing calcite, afwillite, oyelite in float, you are in the right ground. Typical habit: acicular, platy, tabular. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify clinotobermorite?+
Where is clinotobermorite found?+
What rocks look like clinotobermorite?+
What minerals are found with clinotobermorite?+
What kind of rock does clinotobermorite form in?+
What is clinotobermorite used for?+
Find clinotobermorite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
