In America some non-Italian mafias do get labeled as "a mafia" by the FBI. Generally the distinguishing factors between a "gang" and a "mafia" in FBI nomenclature is scale, sophistication, and organization structure/principles. In general, it being a "family operation" (trusting blood family over government or family as government) is a large factor, and often the "omerta" principle is a requirement (that's a strong, core collective binding to secrecy; "omerta" if held as a strong principal "breaks" the prisoner's dilemma game as a law enforcement tool). The Cornbread Mafia, taken apart by the FBI in the 1980s, is one interesting example: https://en.wikipedia.org/wiki/Cornbread_Mafia