.	Dwarves' Earth Treasures Online Museum: Centennial Datolites Centennial #2 Mine, Centennial, Houghton Co., Michigan	.

.    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. About 150lbs of datolites were hauled out and that may accord why the Centennial datolites appeared to one of most commonly encountered beside those coming from Delaware and Caledonia, but even so they are now becoming scarce. It is common 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 roadmaking, so there're not much left coming from the Centennial Mine.
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Typical Centennial Datolite with copper inclusions.
I found this as a rough  in a rock pile at a Rock Shop in Arizona.

Teal colored with some copper inclusions,	Large "mulit-datolite" specimen with greenish colors
Datolite with true sky blue (turquoise) color very rare.	Greenish due to copper inclusions
Another very rare datolite with bluish colors possibly from kinoite inclusions	Datolite filling in epidote lined vug with copper inclusions Found by Jeffrey A, August 1996