Copper 'Skull', Calumet Conglomerate, Calumet & Hecla Mining Company, Lake Superior Copper District, Houghton County, Michigan Small cabinet 3 x 6 x 7 cm $250. Online 1/13/15. SOLD.
Copper 'Skulls' are casts after felsite and rhyolite pebbles in the Calumet Conglomerate. The best examples, as in the case of this specimen, clearly show the original form of the pebble. The interior of this piece is nicely hollow and the reverse looks like a beach worn cobble. The patina is pristine. A Copper Country classic. Mined c. early 1900s. David Strong Collection.