Memento mori
from the Antique Jewelry University
Memento mori jewelry is the name given to 16th through 18th century jewelry that is specifically created to remember a person close to the heart. In the original form they were to remind the wearer of his/her own mortality (the literal translation from Latin is: "remember you must die") and took the form of obscure motives as skulls and coffins. Later it became popular to have hair of the departed person in a locket or ring, often in designs of graveyards and thombstones.