Cognomen เก้าเพชร (Ninphet 
, เก้าเพชร, Kaowpet) , worldwide, is a rare last name. The family name เก้าเพชร is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname, and Malaysia, where it is an extremely rare surname. Very seldom, เก้าเพชร is the forename as well as the last name.