Don’t think I have heard of this tool being sold, but it would be quite easy to make your own “stamp”. Just make a pattern on a scrap piece of plastic and make a mold. You’re good to go. I may have to try that myself. I’m thinking the stuff that model railroaders use to make rock molds will work great. Don’t get discouraged at the thought of having to make your own mold either, its really easy. Hope this helps