That's Colin Farrell wearing a platinum and diamond pavé clover pendant made by the design firm of QuiénSabe or WhoKnowsWho? It's moderately pretty, but the photo is terribly low-res. It was sent to me by a PR firm in LA, however they failed to attribute either the photo or the jewelry. This happens a lot.
He looks like he has the greasy sweats in every single photo he takes, doesn't he? If that picture doesn't put you off your lunch, what will? Would someone please remind me why this person is a movie star?