Sotheby's Paris hosted a fine jewelry auction last month, and several sapphire and diamond rings—much like Kate Middleton's ...

One of the world's rarest diamonds, about the size of an egg or a large lollipop, is going up for auction next month and is expected to fetch $12 million to $30 million.

Whether they turned to an heirloom piece or a trend-forward design, these brides are well-known for their stunning jewels.