Porcupine quills have been used in jewelry, weapons, and items for the home for hundreds, if not thousands of years. The porcupine, a slow-moving creature, who uses his quills to defend himself can have up to 30,000 on his back, making them a readily available source of decoration, provided that you know how to extract them!
The Native Americans were the most ardent users, softening the quills to weave them into leatherwork and basketry. The traditional mohawk headdress, called a porky roach (I lie not), was actually based off the raised quills of a defensive porcupine. The quills were also used in jewelry and detail work for jackets and shirts. With the easy availability of beads, however, these traditional materials fell out of use, so that any type of porcupine quill decorations are fairly rare today.