Grunerite/Cummingtonite (TYPE LOCALITY)

Item Description

Good example of Cummingtonite, a common name for an Amphibole that is rich in Grunerite. Face on, the crystals, which reach up to 3 cm, display its classic, radial growth. Cummingtonite was originally named in 1824 by Chester Dewey for the type locality in Cummington, Massachusetts, USA. Dewey's description of Cummingtonite was not in accordance with modern requirements, so although this is technically a Grunerite, collectors new and old have continued to refer to this Amphibole as Cummingtonite (of Dewey). Previously in the collections of Charles U. Shepard, the Philadelphia Academy of Sciences, and Chris Stefano.