Write an article based on this "Take karat weight into consideration last. Consider selecting an uncommon size karat to save money without sacrificing quality. If buying an engagement ring or gift, find out what the recipient prefers in size. Consider the size of the wearer's hand if buying a diamond ring."
This does not affect the quality of the stone in any way, so a heavier weight does not necessarily indicate a higher quality stone. Note, however, that this may not be possible on a budget. Do you want a slightly smaller stone at higher quality, or the opposite? The most common sizes for engagement rings are 1/2 karat, 1 karat, and 2 karat. People often choose common karat weights, which are known in the industry as ‘magic weights’. Because they are common, the price of diamonds at these weights is usually disproportionately higher than diamonds just below the magic weight e.g. a 0.98 karat diamond may be significantly less expensive than a 1 karat diamond, with no visible difference in size. Not all women prefer many karats. Some may place quality over size while others may be willing to sacrifice a bit of quality for a more noticeable diamond.  Ask the recipient herself about her preference. Ask close friends or family about the recipient's preference. Women with more petite hands may prefer the look of a smaller stone to larger stones that have a tendency to overwhelm. However, women with larger hands may drown out a small stone, making it appear smaller than it really is.