The Ring Of An Engagement? Mary-Kate Olsen Spotted Appraising Neil Lane Rings, As Speculation Mounts She’ll Marry Olivier Sarkozy

Things between Mary-Kate Olsen and her boyfriend Olivier Sarkozy might be getting super-serious, as the fashionista was seen "checking out huge engagement rings at the Neil Lane store" in Los Angeles multiple times last month, RadarOnline.com has learned.

"She really likes cushion-cut diamonds, and all of the rings she has looked at are over five carats," an insider told the NY Post. "She has narrowed it down, but still hasn't made a final decision."

A separate insider -- noting that some of the jewelry Olsen browsed was upwards of $100,000 -- said they doubted "price was an issue."

Olsen, 27, and Sarkozy, the 44-year-old half-brother of France's President Nicolas Sarkozy, have been dating since 2012. The one-time child star was formerly seeing artist Nate Lowman before a 2010 breakup.