Depending on where you live the average engagement ring size will vary. The 1.0 carat center stone used to be the most desired size chosen for engagement rings, however, more recently we are seeing this shift towards a slightly larger stone, with couples choosing diamonds averaging 1.25 to 1.50 carats.

With natural diamonds, you can get approximately a 1 to 1.25-carat diamond for $3,000. If you choose a lab-grown diamond instead, you can get approximately a 2.5 to 3 carat stone. Just remember that if your budget is $3,000 total, you will need to opt for a smaller diamond in order to afford the setting, too.

The Most Popular Engagement Ring Shape: Round "A round-cut is cone-shaped to maximize light return through the top of the diamond and looks stunning in every type of setting." You can't beat a classic (yet).

A good quality 1 carat diamond ring costs between $6,500 to $7,500 in retail stores, while the same diamond will cost about $3,000 - $4,000 online! On the other hand, the highest quality 1-carat diamond (D color and Flawless) will set you back $10,000 or more (add 40-70% when purchased at a jewelry store).