A diamond's weight is measured in carats. Nothing makes a woman's ears perk up like the word carat when paired with the word diamond!
Once you've determined what cut, color and clarity appeal to you, the carat weight may be the easiest to determine according to budget. The traditional engagement ring centerstone weighs around 1-carat yet there are a number of considerations to be made that effect this decision such as the size of the finger, size of the setting and the recipient's style and lifestyle. A smaller diamond centerstone may work better for someone in the medical field who washes their hands repeatedly throughout the day just as a larger stone may appeal more to a woman working in P.R. Furthermore a smaller stone may look quite substantial on a smaller sized finger. The decision is ultimately a personal choice based on the recipient's overall tastes.
When diamonds are mined, larger stones are found much less often making them singularly rare and thus more expensive. Therefore, a larger diamond of the same cut, color and clarity will increase in price exponentially with carat weight. Furthermore two 1-carat diamonds will often be less expensive to purchase then one 2-carat diamond of equal cut, color and clarity.