Email Me .
Dwarves' Earth Treasures Online Museum:
Caledonia Datolites
Caledonia Mine, Mass City, Ontangon Co. Michigan
.
    Caledonia Mine is the only Michigan copper mine I know of that is still active, mainly for purpose of specimen collecting, and it's well known for its datolites that are almost always colored (mainly brownish red). I had been in one adit of the mine several times to try my luck at finding datolites, copper, silver, calcite and others as well as a chance to say hi to few bats (I don't see how can some people be scared of them, how absurb...). It appeared that the Caledonia Mine contained few different types of  mud-filled datolite seams and some of them are accessible to guided tour of collectors.

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, and
the seam tend to fall apart littering the ground with so many small datolites.