When you think of where to buy your engagement ring, you might think of Zales, Tiffany & Co., or Blue Nile. But if you've ever walked past the diamond counters at a Costco warehouse, you might be ...

Tiffany & Co. is suing Costco for allegedly marketing engagement rings as "Tiffany" brand. The lawsuit claims Costco sold engagement rings in stores under the label "Tiffany" in stores but never ...

Costco owes more than $19 million, a federal judge ruled Monday, for selling engagement rings it named after the storied jewelry shop Tiffany’s. MANHATTAN (CN) — Finding that Costco’s so-called ...