Manandonite is a rare lithium-bearing silicate mineral belonging to the chlorite group that typically forms thin, flexible, micaceous plates. Collectors prize it for its unique chemistry involving boron and its occurrence in complex lithium-rich pegmatite environments.
Is this manandonite?
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 manandonite with a known reference. Manandonite sits at Mohs 2.5, 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: pearly on cleavages.
- 4Match the color rangeCompare against the expected color range: colorless, pearl white.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: massive, micaceous, pseudo hexagonal.
Often confused with
Manandonite vs. its common look-alikes, and how to tell them apart in the field.
How to tell apart: Luster reads pearly on cleavages on Manandonite and vitreous to pearly or silky on Muscovite.
How to tell apart: Streak differs, so Manandonite leaves white, Clinochlore leaves greenish white to white.
Often found alongside manandonite
Minerals reported to co-occur with manandonite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- Li₂Al₄(Si₂AlB)O₁₀(OH)₈
- Mohs hardness
- 2.5
- Density
- 2.76-2.89 g/cm³
- Colors
- Streak
- White
- Luster
- Pearly on cleavages
- Transparency
- Transparent to translucent
- Crystal system
- Orthorhombic
- Crystal habit
- Massive, micaceous, pseudo hexagonal
- Cleavage
- Perfect on {001}
- Rarity
- Rare
- Uses
- Collector
- Host rock
- In miarolitic cavities developed in corroded differentiated quartz-microcline-tourmaline-bearing pegmatites
Where rockhounds find manandonite
Classic worldwide localities
- Antandrokomby pegmatite, on the Manandona River, Sahatany Valley, Madagascar
Field-hunting tip
Where it forms: In miarolitic cavities developed in corroded differentiated quartz-microcline-tourmaline-bearing pegmatites. If you start seeing elbaite, quartz, microcline in float, you are in the right ground. Typical habit: massive, micaceous, pseudo hexagonal. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify manandonite?+
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Find manandonite on the map
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