Biotite Mica (unusual shape !) on Calcite

Item Description

It is difficult to find a mica specimen to rave about but this one really DOES draw the eye, because of the geometry. It presents as a pseudo-triangular crystal, 3 cm on each edge, perched nicely in a well trimmed matrix of calcite. "mica" would not be your first thought as to what this is, from the shape. This is a unique, unusual specimen, and was in the collection by the 1970s as #790 in Jack's collection. Cannot say as ew have seen another quite like it! We are honored to present another lot of deaccessions to auction from the collection of Jack Halpern of San Francisco, as featured in the Mineralogical Record, March 2005.