SERPENTINE
Specimen ser-2
$ 25.00Dims: 4" x 1-7/8" x 1"
Wt: 2.6 oz
Chestnut Hill, Easton, Pennsylvania, U.S.A.
Not only have I never seen one of these specimens before, I never heard of such a transformation occurring! This specimen is a Serpentine pseudomorph after biotite; it's variety name is Eastonite, most likely named after Easton, the town in which this mineral was found. It looks a lot like a muscovite book, but is a little bit less "micaceous" looking, and looking at the sides perpendicular to its basal faces, some parts of it look definitely like serpentine. Bizarre!