Mesolite Mineral Guide

Mesolite

Crystal system · Orthorhombic

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

About Mesoliteextended article

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

1
Talc 2
Gypsum 3
Calcite 4
Fluorite 5
Apatite 6
Orthoclase 7
Quartz 8
Topaz 9
Corundum 10
Diamond

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.

More minerals to explore

About Mesolite

Mesolite belongs to the silicate class in the zeolite group (natrolite subgroup) and has the chemical formula Na2Ca2[Al2Si3O10]3·8H2O. It crystallizes in the orthorhombic system and holds a steady position among silicate species.

Identification & care

Mesolite typically forms acicular to hair-thin crystals in radiating tufts; cotton-like masses. Its color is typically colorless and white. The luster is silky to vitreous, the streak is white, and specimens range from transparent to translucent. The cleavage is perfect {110}. The fracture is uneven, which aids identification.

Collector context

Collector notes

For collectors, Mesolite is a benchmark crystalline species.