It opens and closes securely and could house a lock of hair or photo. I love it empty as it is sleek and has a remarkably contemporary look. It measures 5/8 inches without the O ring and 7/8 inches with the top ring. The condition of the crystal is excellent. The mellow rose gold is in excellent condition as well. It can be worn on the neck or on a charm bracelet. It is especially pretty as the light magically illuminates the crystal.