Images
Formula: Ca12Al14O32[☐(sub>4Cl2]
Multiple oxide, mayenite supergroup
Crystal System: Isometric
Specific gravity: 2.85 calculated
Streak: White
Colour: Colourless
Environments
The mayenite supergroup species show unique electrochemichal properties,
with some anions in their structure (such as
oxygen anions) migrating thorough the structure. As such, the mayenites
behave as metals even though they are very non-metal in terms of general chemistry. Transitions seen in their
structure may be related to superconducting. The mayenites represent a group
of chemicals known as "salts of an electron", also known as electrides
(Mindat).
Localities
At the Basalt quarry, Klöch, Südoststeiermark District, Styria, Austria, chlormayenite is associated with
melilite, wollastonite,
kalsilite, brownmillerite and
corundum
(HOM).
There are two co-type localities, Mayener Feld, Mayen, and Ettringer Feld, Ettringen, both at Vordereifel, Mayen-Koblenz
District, Rhineland-Palatinate, Germany. Here chlormayenite occurs in thermally metamorphosed
limestone blocks included in volcanic rocks. The chlormayenite is
found as colourless rounded grains having no recognisable crystal faces, with a maximum diameter of 60 microns.
Associated minerals include calcite,
ettringite, wollastonite,
larnite, brownmillerite,
gehlenite, diopside,
pyrrhotite, grossular,
spinel, afwillite,
jennite, portlandite and
jasmundite
(AM 50.2106-2107).
At the Hatrurim Basin, Tamar Regional Council, Southern District, Israel, chlormayenite is common in
high-temperature, thermally metamorphosed, impure limestone. Associated
minerals include spurrite, larnite,
grossite and brownmillerite
(HOM).
Back to Minerals