The radula of Patella limpets has cutting tips that incorporate magnetite crystals and silicon dioxide.

“Another mollusk, the limpet Patella, backs the magnetite cutting tips of its radula with silicon dioxide (Runham et al. 1969). Incidentally, mollusks renew their radulas from the back as they wear near the front much the way elephants renew their teeth.” (Vogel 2003:333)

“Most classes in the phylum of the Mollusca possess a radula, a flexible
ribbon, located in the mouth cavity, on which are implanted several
tens of transverse rows of teeth. The radula is used as a rasp during
feeding of organisms living on rocky substrates. Through the continuous
growth of the radular ribbon new rows of teeth steadily enter into the
wearing zone, while at the same rate teeth in the last row break loose
from the ribbon. The enhanced erosive capability of the radula is due to
the presence of teeth with an upright standing, hard, mineralized
cusp.” (van der Wal et al. 2000)

Last Updated September 14, 2016