I'v got about 35lbs of black slate. I'll sell it for .50 pound. Shipping will be $10 to ship as much that will fit into a 11''x8.5''x5.5'' box. Here is some pics. Some of the rocks have white line running across them. If you want you can take the thicker peices and hit them with a chisel on the sides and they will split so you can make them as thin as you want. You can also just hit them with a hammer to make them smaller peices.
in tank
thick
thin
wet
wet2
white line
all dry
in tank
thick
thin
wet
wet2
white line
all dry
