Leonardo DiCaprio may be dating Victoria’s Secret model Bar Rafaeli, but he’d only buy a diamond for his mom, Irmelin.

The actor, 32, who stars in the upcoming drama Blood Diamond, about the lives that are destroyed by the mining of “conflict diamonds,” was asked by reporters at a junket for the film whether he feels differently about buying diamonds since making the movie.

“Well, I don’t remember the last time I have,” he said. “My mom is the only person that I would buy something like that for, and for a while now she hasn’t wanted one. But that isn’t to say that people shouldn’t buy them.”

How can consumers make sure they’re not buying conflict diamonds? “From my conversations with Global Witness or Amnesty International, you have to go into the stores and buy these diamonds and ask for a certificate, ask for some sort of authentication that this isn’t a conflict diamond,” he said. “That’s one of the biggest ways that this whole process can be put to a stop.”

He also said he and costar Djimon Hounsou spent a lot of time hanging out in muddy swamps while filming the movie. “We would sit there and talk about the different kinds of hot chocolates that you can get in Paris and the croissants. We’d sit there and dream like two weird women about pastries.”