Sea urchin spine necklace

THis is a very cool necklace if you like shells and ocean related jewelry. I was told these are actually sea urchin spines. They are hard like shells. Each spine is about 1 1/2" long. Necklace is 13" doubled as shown. Strung on nylon line. Only one of the spines are damaged. Spaced with red and yellow seed beads. Unique