Mary-Kate and Ashley Olsen are bringing feathers back in their Fall 2010 collection. They’re adding leather, and a couple of inches to the heels of their booties, but it’s the diamonds that caught our eye in their showroom this morning.

While they’ll continue to produce their most popular jewelry pieces from seasons past, they’re adding fine jewelry for spring. And though Robert Lee Morris will continue its production, the girls are dropping his name from the line and its promotion, because the Olsens have actually designed the new collection.

The white and gold diamond necklaces, bar rings, and pendants will sell in stores like Neiman Marcus, instead of Bloomingdales, and prices go up to the thousands of dollars. They should add rough diamonds to The Row.