We refer to it as wax, but it is more like a plastic polymer which allows us to file, cut and carve it. There is a variation in hardness available. Green is my favourite. I like that is is a little more brittle and it carves very well. This model will be cast in gold after I am happy with the general shape. Then I file, sandpaper, finesse it, set the stones, and then put a final polish on it.