Tagua Nut slices also work well for cutting jewellery from, I have cut pendants from them before.
The slices are thin and very tough and durable, but quite easy to cut. The size makes it a little fiddly to hold but you can make up a rig for them similar to ones people use to cut coins or compound items.
There are a few online places on the net, one of these being: http://www.acaibeads.com/ThinTaguaSlices.html