May I suggest making your own with plaster of paris as the "rock."  The
only place you are going to find pots in rock is in volcanic areas.
Perhaps mud or clay would be a more appropriate matrix.

Many museum stores sell the kits you describe.  Why don't the
archaeologists take a tip from Jurassic park and prepare their specimens
with a helicopter- but I digress.. good luck.

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Christopher Whittle                         College of Education &
Box 72119                          Department of Earth and Planetary Sciences
Albuquerque, NM 87195                       University of New Mexico
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