Pumpellyite-(Fe2+)
Pumpellyite is a group of closely related sorosilicate minerals: pumpellyite-(Mg): Ca2MgAl2[Si2O6OH][SiO4](OH)2(OH) pumpellyite-(Fe2+): Ca2Fe2+Al2[Si2O6OH][SiO4](OH)2(OH) pumpellyite-(Fe3+): Ca2Fe3+Al2[Si2O6OH][SiO4](OH)2O pumpellyite-(Mn2+): Ca2Mn2+Al2[Si2O6OH][SiO4](OH)2(OH) pumpellyite-(Al): Ca2AlAl2[Si2O6OH][SiO4](OH)2O Pumpellyite crystallizes in the monoclinic-prismatic crystal system. It typically occurs as blue-green to olive green fibrous to lamellar masses. It is translucent and glassy with a Mohs hardness of 5.5 and a specific gravity of 3.2.
Intro adapted from Wikipedia (CC BY-SA).
Pumpellyite-(Fe2+) is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₂Fe²⁺Al₂(Si₂O₇)(SiO₄)(OH,O)₂·H₂O.
It crystallizes in the monoclinic crystal system (space group A2/m). It is a member of the Pumpellyite structural group.
Key properties: Mohs hardness 5; specific gravity 3.31; [Vitreous.] luster; optically biaxial.
IMA symbol Pmp-Fe2+, IMA status: approved, named in 1973.
Found in the contact zone around an intrusive.
It is found associated with Prehnite, babingtonite, clinopyroxene, calcite.
The name refers to its membership in the pumpellyite group and dominant ferrous iron content.