Cervandonite-(Ce)

cervandonite-(Ce)

asbecasite

cafarsite

chernovite-(Y)

Images

Formula: (Ce,Nd,La)(Fe3+,Ti,Fe2+,Al)3O2(Si2O7)1-x+y(AsO3)1+x-y(OH)3x-3y
Sorosilicate (Si2O7 groups), cerium-, neodymium-, lanthanum-, titanium- and arsenic- bearing mineral
Crystal system: Trigonal
Specific gravity: 4.9 calculated
Hardness: 5
Streak: Brownish black
Colour: Black
Environments

Metamorphic environments

Localities

There are two co-type localities, the Monte Cervandone area, Devero Alp, Baceno, Verbano-Cusio-Ossola Province, Piedmont, Italy and the Wanni glacier - Scherbadung area, Binn, Goms, Valais, Switzerland.

At the type localities cervandonite-(Ce) forms small (typically less than 1 cm), lustrous rosettes of curved, jet-black crystals, some with blue-green iridescent surfaces, commonly resting on quartz or albite. It can be found throughout the Binntal-Cervandone-Devero region. The largest specimens have come from around the Wannigletscher, with aggregates exceeding 2 cm. It is typically associated with other arsenic species characteristic of the area, including asbecasite, cafarsite and chernovite-(Y), and with hematite, magnetite and rutile. In the Lärcheltini Zone, cervandonite-(Ce) is sometimes associated with graeserite (MinRec 56.3.309-310).
Cervandoite-(Ce) from the Monte Cervandone Area - Image

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