Centennial Mine, Keweenaw Peninsula, Michigan
Circa 1930
2.8 x 2.5 x .5 inches
SOLD ON EBAY

The calcite crystals are very gemmy which, combined with the exceptionally brilliant included copper crystals, makes for a world-class display. This specimen consists of two somewhat cone-shaped forms, one about half the size of the other. There is a secondary growth of smaller calcite crystals on top of the larger, heavily copper-included crystals. These smaller crystals are only on one side of the specimen, which makes for a fantastically aesthetic effect.