Jasmundite

jasmundite

ettringite

brownmillerite

larnite

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Formula: Ca11O2(SiO4)4S
Nesosilicate (insular SiO4 groups)
Crystal System: Tetragonal
Specific gravity: 3.03 measured
Hardness: 5
Streak: White
Colour: Pale to smoky green, also greenish brown
Solubility: Soluble in dilute hydrochloric acid
Common impurities: Al,Fe,Mg
Environments

Metamorphic environments

Jasmundite occurs in metamorphosed limestone inclusions in basalt (Webmin).

Localities

At the type locality, Ettringer Feld, Southern lava flow, Bellerberg volcano, Ettringen, Mayen, Mayen-Koblenz, Rhineland-Palatinate, Germany, jasmundite occurs in metamorphosed limestone xenoliths in basalt (Mindat, HOM, Dana) as irregular grains, up to several millimeters in size, intergrown with mayenite, brownmillerite and larnite, or associated with portlandite and ettringite (AM 69.566). Other recorded associates include calcite, vaterite, tobermorite and thaumasite (HOM, Dana).

At Jebel Harmun, Quds Governorate, West Bank, Palestine, dzierżanowskite was found in larnite pebbles which are embedded in a low-temperature mineral matrix. Associated minerals are larnite, brownmillerite, fluorellestadite, ye'elimite, gehlenite, periclase, ternesite, nabimusaite, vorlanite, vapnikite, fluormayenite, fluorkyuygenite, oldhamite, jasmundite, covellite, chalcocite and pyrrhotite (MM 81.5.1073–1085).

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