What actors and actresses appeared in Diamante bruto - 1977?

You're likely referring to "Rough Diamond" (Diamante bruto) which was released in 1979, not 1977.

Here are some of the main actors and actresses who appeared in "Rough Diamond":

* Fernando Rey as Inspector Medina

* Jose Luis Lopez Vazquez as Juan "El Diamante"

* Silvia Munt as Clara

* Jean-Louis Trintignant as Carlos

* Alberto de Mendoza as The Lawyer

* Luis Ciges as The Dealer

* Lidia Bosch as The Secretary

Let me know if you want information about other roles in the film!