Laser engraving uses a high-powered laser beam to etch the surface of the material that is being engraved. Similar to the mechanical rotary engraving machine, the design that you want is programmed into the computer and the machine will engrave the design that you want into the jewelry. Although you can use a charm as a pendant and vice versa, here are the technical differences between the three. Pendants are pieces that are 25mm or larger (not including the bail, loop or jump ring). If it does not have a bail, loop or jump ring, then its hole will be drilled or punched from front to back. Cable chains, box chains, curb chains, figaro chains, and wheat chains are all great chain styles to consider for pendants. Again, adjust the width accordingly if you decide to wear these chains with a heavier pendant for extra durability.