Jasper isn't an expensive stone, but many inexpensive natural stones don't come in the shapes or SIZE that I want. Good thing that Tory Hughes showed me how to mimic lapis lazuli (which isn't inexpensive) and turquoise in her book Polymer: The Chameleon Clay.
I've used combinations of those techniques again and again as a springboard for faking real and fantasy materials. Witness my latest adventure with "red jasper":
Can you believe that this mess
got molded into this
and ended up looking like this?
Then it was transformed into this?
BELIEVE. With polymer, almost anything is possible....