Pumpellyite Subgroup

The pumpellyite subgroup 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)

The pumpellyite subgroup is a member of the pumpellyite group.


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.

At the Central No. 2 shaft, Central Mine, Central, Keweenaw county, Michigan, USA, a 1.49-mm needle of pumpellyite with a microsphere of hematite attached has been found in a void in conglomerate (R&M 97.4.357).

Back to Minerals