This is a rock made of wax.... my favorite carving medium. This particular wax is a stiffer mineral filed which can be cast and cleanly carved with a jeweler's wax carving tools or woodworking and carving tools. I cast this wax into a urethane rubber mold and put it in a vacuum chamber to rid all possible air bubbles. It captures the detail of a fingerprint.
Polytek: "Poly Wax 15 is a white, hard, low shrinkage, mineral-filled wax which can be cast and carved. When cast into rubber molds, it replicates the mold surface in detail and finish. Tool cuts are smooth and lustrous. Dull surfaces can be hand polished with a soft cloth to a satin luster. Ideal for prototypes, models, masters and carving blanks from rubber molds of rough originals."
Here is the finished rock cast in super concrete