Pumpellyite

pumpellyite

chlorite

analcime

prehnite

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The pumpellyite group of minerals includes:
Pumpellyite-(Al): Ca2Al3(Si2O7)(SiO4)(OH,O)2.H2O
Pumpellyite-(Fe2+): Ca2Fe2+Al2(Si2O7)(SiO4) (OH,O)2.H2O
Pumpellyite-(Fe3+): Ca2(Fe3+,Mg)Al2(Si2O7)(SiO4) (OH,O)2.H2O
Pumpellyite-(Mg): Ca2MgAl2(Si2O7)(SiO4)(OH,O)2.H2O
Pumpellyite-(Mn2+): Ca2Mn2+Al2(Si2O7)(SiO4) (OH,O)2.H2O
These are all sorosilicates (Si2O7 groups)
Hardness: pumpellyite-(Mg) 5½
Streak: pumpellyite-(Mg) white
Colour: Greenish black due to divalent iron Fe2+, green due to manganese Mg, blue, blackish green, brown, pale grey due to divalent manganese Mn2+, pink-brown
Environments:

Metamorphic environments

Pumpellyite is characteristic of the prehnite-pumpellyite facies, and it is also a mineral of the blueschist facies.
Pumpellyite and prehnite form from calcium zeolites in the presence of calcite.

Localities

La Flèche quarry, Bertrix, Luxembourg, Wallonia, Belgium, is the type locality for pumpellyite-(Al).

Forra di Bulla, Kastelruth, Salten-Schlern, South Tyrol, Trentino-Alto Adige, Italy, is the type locality for pumpellyite-(Fe3+).

Ochiai mine, Kohsai, Minami-Alps City, Yamanashi Prefecture, Japan, is the type locality for pumpellyite-(Mn2+).

The Ivakin Creek, Noril'sk, Putoran Plateau, Taimyr Peninsula, Taymyrskiy Autonomous Okrug, Krasnoyarsk Krai, Russia, is the type locality for pumpellyite-(Fe2+).

At Croft Quarry, Croft, Blaby, Leicestershire, England, UK, the prehnite-pumpellyite wall-rock alteration haloes that surround the zeolite - containing veins in the quartz - diorite contain pumpellyite-(Fe2+), associated with prehnite, chlorite, quartz and analcime, and also minor muscovite variety sericite, kaolinite and smectite (JRS 20.23).

Keweenaw county, Michigan, USA, is the type locality for pumpellyite-(Mg).

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