Most DIY/Hobbyist 3D printers are FDM printers. These DIY machines cannot use sandstone or silver. DIY FDM Printers will most commonly use ABS and PLA plastics. With nylon, wood (laywood-3), HDPE, HIPS, PET being other materials that people are experimenting with.
A 3d printer is nothing but a hot glue gun on rails. The secret to printing is having a material with an obtainable melting point that does not outgas chemicals into the air and hardens quickly. If a material can reach that criteria, there is probably some way to print with it.