Mesolite

Mesolite is a silicate mineral recognized among collectors for its crystal form and distribution.

Mohs 5
Vickers (~) 540 HV
Knoop (~) 620 HK
Geological setting
Volcanic
Element composition by mass

Formula: Na₂Ca₂Al₆Si₉O₃₀·8H₂O · molar mass: 1038.78 g/mol

O 47.75%
Si 24.33%
Al 15.58%
Ca 7.72%
Na 4.43%
H 0.19%

Computed from atomic weights (IUPAC 2021). Site-occupancy groups (Fe,Mn) split equally.

Mohs Hardness 5

Mesolite sits at 5 on the Mohs scale — can be scratched by a steel knife.

Colors:
Streak
White
Crystal system
Orthorhombic
SilicatesSilicates (Tectosilicates — Zeolites)
TL;DR · 1 min read
Mesolite (Na₂Ca₂Al₆Si₉O₃₀·8H₂O) is the intermediate Na-Ca zeolite between natrolite (Na) and scolecite (Ca). It forms hair-like acicular crystals — sometimes meters-long and finer than human hair — in radiating tufts and snow-white aggregates.

Mesolite (Na₂Ca₂Al₆Si₉O₃₀·8H₂O) is the intermediate Na-Ca zeolite between natrolite (Na) and scolecite (Ca). It forms hair-like acicular crystals — sometimes meters-long and finer than human hair — in radiating tufts and snow-white aggregates. Pune (India) and Iceland supply iconic snow-white “cotton ball” mesolite specimens.

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