Heavy black massive specimen containing the rare earth element cerium. Perrierite is usually metamict
Cerium is used in the manufacture of battery alloys, metal alloys, catalysts in autos, and glass additives to name a few. From the 1950's to the 2000's it was used in lapidary polishing agents. Price increases eliminated the use. Aluminum and titanium oxides are now used.
Best ref.: Arthur A. Pegau (1932) Pegmatite Deposits of Virginia. Virginia Geological Survey; Bulletin 33.