Online diamond retailer Blue Nile is adding fancy-colored diamonds to its repertoire. The company reports that it is doing well with high-end buyers. Seven items with price tags over $100,000 were sold in Q1 this year. Blue Nile’s current selection of fancy-colored diamonds include a range of yellows, a couple pinks, and a few light greens. At the very top of the price chart is a 0.55 carat purplish-red for $350,000.