Unique 14k yellow gold 24" large Antique heart locket with 0.06ct diamond question mark, circa 1902. The question mark became popular in jewelry in the second half of the 19th century, after spiritualism and mysticism took hold, which was also a period marked by an interest in whimsical and playful designs and elements of surprise. The question mark became a unique and beautiful symbol of the unpredictability of life and multitude of possible outcomes.