Pinky rings have several historical meanings; they can indicate a lack of interest in pursuing marriage, a person's self-identification as gay or an involvement with organized crime. Signet rings are also often worn on the pinky finger. In addition pinky rings are often given as graduation symbols to engineering students.
During the 19th century, men and women both wore pinky rings on their left hands to indicate they were not interested in marriage. In the 1950s and 1960s, gay men and women wore pinky rings to identify themselves to others in the gay community. Pinky rings have long been associated with criminal activity. Members of the Mafia who had killed people traditionally wore them, as did grifters.
Some people simply wear pinky rings as a fashion statement; they first became popular in Paris in the early 20th century. People who wear pinky rings with no symbolism often choose them because they cannot be confused with wedding rings and do not interfere with the pointer fingers. Some women wear silver rings with diamonds on their pinky fingers to signal they are either "available and happy" or "attached and happy."
Some pinky rings are professional symbols. Engineering students in the United States and Canada are given pinky rings upon graduation. Geologists, geophysicists and human ecology majors also receive pinky rings.