Gisele Bündchen will auction off some of her jewelry October 15 at Christie's. Two rocks hitting the block were reportedly given to her by ex-boyfriend Leonardo DiCaprio: One colored diamond ring could fetch $15,000 to $20,000, and another diamond pendant necklace could go for $150,000 (so clearly she dumped him because he's cheap). Two more giant diamonds are expected to go for $2 million to $4 million together, with a portion of the proceeds benefiting a nonprofit organization that empowers African diamond-mining countries. [WWD]