Millennials are blamed for disrupting a lot of industries, from cereal to soap, and now they're wreaking havoc on the jewelry industry. Customers today want timeless pieces that aren't so expensive they require a down payment, and they want to be able to collect items that can be customized into a truly personal look. In addition, they're browsing jewelry online and designing unique pieces. And young consumers are waiting longer to get married -- putting a dent in the engagement ring category -- and increasingly considering lab-made diamonds and other stones. These trends have put mainstream players like Signet's Zales, Kay and Jared in a tough spot. Lindsey Rupp and Kim Bhasin take a look at the changing trends in the industry and talk with New York startups Rebe and Catbird about what might be coming next.