Blue Nile and Amazon said sales were strong at Christmas. Seattle-based Blue Nile reported fourth-quarter net sales of $90.7 million, a 23.9 percent increase over 2005. The company also named its chief financial officer, Diane Irvine, to the post of president.

Amazon.com said its fourth-quarter 2006 jewelry and watch sales more than doubled, although it did not provide numbers. Shipments of diamond stud earrings were up 130 percent, and gemstone jewelry rose 100 percent.