I had some major problems with the chips, because I wasn't sure on what orientation I was going to want them to have I made the whole object, used a cylinder on each face of the chip in a difference to give the indented effect and to put the chequered pattern in the middle of the chip.  I decided that I wanted to be able to see the original colour of the chip through the chequered pattern so filtered the pigments that made up the chequered pattern and hey presto, a disaster.  When I do this you can see right through the chip, as though there is none of the original material in the object between the chequered patterns on each side of the chip.

Any suggestions?

Steve