There are few things more gawk-worthy than a celebrity engagement ring. The world's rich and famous have a tendency to adorn their betrothed with some of the biggest, brightest, and (of course) priciest diamonds.

From Blake Lively's roughly 12-carat oval-cut bauble valued at approximately $2 million from hubby Ryan Reynolds to Beyoncé's 20-carat stunner from Jay Z, valued at a cool $5 million, these diamonds are definitely a girl's most expensive friend.