Amanda Anka has this to thank fiancé Jason Bateman for: a three-and-a-half-carat diamond in a delicate twenties ... when he offered her a little blue box. Inside? A three-carat Lucida-cut ring ...

Its combined first and second tenders, however, indicated a 13% increase in overall average prices, thanks to an improved product mix, which included a standout 18.85-carat blue diamond from ...