Herschelite (Chabazite-Na)
Image: <a href="//commons.wikimedia.org/wiki/User:Archaeodontosaurus" title="User:Archaeodontosaurus">Didier Descouens</a> (CC BY-SA 4.0)
Mineral NameHerschelite (Chabazite-Na)
Chemical FormulaNa2Al2Si4O12·6H2O
Mohs Hardness4.5
Crystal Systemtrigonal
Lustervitreous
Streak Colorwhite
Cleavagedistinct on {1011}
Fractureuneven to conchoidal
Specific Gravity2.05
Colorswhite, colorless
Transparencytransparent
Type LocalityRupe di Aci Castello, Aci Castello, Etna Volcanic Complex, Catania Province, Sicily, Italy
Mineral GroupSilicates (Zeolite Group)
Usescollector, industrial (molecular sieves, ion exchange)
Associated Mineralsphillipsite
Rarityuncommon
Description
The image displays a vug in a dark, porous volcanic matrix, lined with numerous small, sparkling white to colorless crystals, along with a few larger, more distinct, transparent rhombohedral crystals.
Geological Context
Herschelite, a zeolite mineral, typically forms as a secondary mineral in the vesicles and fractures of basaltic volcanic rocks, crystallizing from late-stage hydrothermal solutions at low temperatures, as found in the Etna Volcanic Complex.
