Kate Bock is basking in her engagement ... t involved in the ring design at all. Kevin did it all himself," she tells PEOPLE. "It's gorgeous. I couldn't love it more! It's a vintage diamond ...

A vintage four-carat Boucheron ring from husband ... Heidi Klum's most treasured trinket? Probably the engagement ring set with three round stones that she got from hairstylist Ric Pipino.