Dwarves' Earth Treasures Online Museum:
Centennial Datolites
Centennial #2 Mine, Centennial, Houghton Co., Michigan
Field-collecting Status: Mine Dumps Mostly Gone. Collect at one's own risk.

.    There was a story of the miners hitting on a huge seam of datolites and they used water hose to wash the datolites out of the mud-filled seam. At least 150lbs of datolites were hauled out and that's explain how the Centennial datolites used to be one of most commonly encountered beside those coming from Delaware and Caledonia mines, but now they're now becoming scarce. It's typical for the Centennial datolites to contain native copper inclusions and some of those datolites got their green and rarely sky blue colors from the weathering of copper inclusions (paraatacamite, chrysocolla, and kinoite) by ancient brine waters.  As of today, much of the rocks had been hauled from both Centennial #3 and #2  mine dumps to be crushed for purposes of road making, so there're not much left coming from the Centennial Mines.
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Teal colored with some copper inclusions,	Large multi-chambered specimen with greenish colors	Datolite sky blue (turquoise) color
Datolite with bluish colors possibly due to kinoite inclusions	Datolite with bluish colors possibly due to kinoite inclusions
Typical Centennial Datolite  with copper inclusions. I found this as a rough  in a rock pile at a Rock Shop in Arizona.	Datolite filling in epidote lined vug with copper inclusions Found by Jeffrey A, August 1996