I've seen photos of a large wide cross on a chain, from a Brazilian prospector, made of gold he found. Back in school classroom, it was art class, they taught us how to cast silver rings. You need a type of casting wax to cut and carve for a ring. The metal is melted in a kiln, wax ring carving packed in casting sand. A type of centrifuge spins the molten metal through a hole in the sand casting toward the wax carving, melts then replaces the wax. The casting sand is a jewelry grade type nice and fine for this work.