The six-pointed Star of David, a symbol of Judaism, is frequently found on Jewish tombstones. It is also called the Shield of David (Magen David in Hebrew). Sometimes you will see the Hebrew abbreviation “Peh-Nun” inside the star like the example here. This abbreviation stands for either “poh nitman” or “poh nikbar” and means simply, “here lies…”
For more information on Jewish tombstone iconography see: Reading Hebrew Tombstones.
Photo: from the headstone of Rose Simon (1906-1934), Emanuel at Fairmount Cemetery, Denver, Colorado