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Clay versus Mud - Is there a difference?
W. David Hoisington, Ph.D.
There is often brown mud in connection with Herkimer diamond pockets, but is some instances there is clay in the pocket. It is a clay that has a greasy feel to it, like the feel of baby powder. It can be white, but it has been seen as yellow (TCR) and as black (HBQ).
It is proposed here that the clay is different than the mud. The mud is post-glacial in origin. It is ground water reworked material. But the clay may have a different origin.
Investigations on the clay are preliminary at this time (2011).
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The photos here serve as clear examples of clay in the Herkimer district.
Photo 1: This sample from DA was the first "in place" clay that was convincing. It was a tight vug in solid rock. The clay is much lighter than in this photo, appearing almost white (see photo 5).
Photos 2 and 3: A close up of photo 1 to show the compact nature of this clay and to distinguish it from the texture of the more common brown mud, shown in photo 3.
Photo 4: A handful of yellow clay (probably rust contaminated white clay) from a Herkimer pocket at TCR (2010). A large amount of this was found, taken out of the ground and put into a mound. After a few rains no sign of it could be found.
Photo 5: From TCR (2010), here you can see the white clay and what seems to be an intertwined relationship with the black hydrocarbon (like photo one). A 2 mm second phase dolomite crystal can be seen bottom right.
Photo 6: Photo donated by Mike Eggleston (2008) and it is of a skeletal crystal from Treasure Mt. It is an excellent picture of the white clay coating (arrow points) the crystal faces of the "skeleton" which are inside the crystal.
Awaiting microscope work
Photo 2 ->
More photos to come