.	Dwarves' Earth Treasures Online Museum: Caledonia Datolites Caledonia Mine, Mass City, Ontonagon Co. Michigan	.

    Caledonia Mine is the only Michigan copper mine I know of that is still active, mainly for purpose of specimen collecting. Copper and silver specimens had been found by the people on the guided collecting tours during the Keweenaw Week in August. The mine is one of several mines that are best known for the colored and the unusual thing about the datolites from there is that they're almost always colored with brownish red being the typical color. Occasionally, the datolites in other colors like blood red, orange, peach orange, and pink and some of them come with epidote inclusions. Sometimes the datolites are found in their vein forms usually with episode, calcite and copper. The datolite nodules are found mainly in the mudslide cracks in one of those big sloping mining rooms and some are still found in the mine piles outside the adit. The mine is currently owned by Red Metal Retreat company.
Click on to see larger map.
Datolites below are bought by JA

Typical color of Caledonia Mine. Has copper specks all over.	Blood Red!
With copper inclusions	I don't know what to call that unusual color.
An example of what a datolite seam would look like.  Such the seam tend to fall apart when taken out of the "mudrocks", litter the ground with many smaller datolites	Sharp Color zoning

Vein Datolite with copper and silver from
1100 feet level of Caledonia Mine