Cognomen พันธุ์เพชร (พันธุ์เพชร 
, Phanphet , Phaephet ) , in the world, is a rare family name. The cognomen พันธุ์เพชร is characteristic of South-eastern Asia, particularly Thailand, where it is a rare surname. Much less frequently, พันธุ์เพชร is the forename as well as the last name.