Although buying a 1-carat diamond is a benchmark for many couples, the truth is very few people can distinguish between a 1-carat stone and a 0.9- or 0.8-carat stone. That's good news for engaged couples since this minuscule difference in weight makes a major difference in price.
There's about a 30 percent price difference between a 0.9-carat and a 1-carat stone, says jewelry designer Sylvie Levine, co-owner of The Sylvie Collection, an engagement ring line. The same difference is found between 1.4 and 1.5 carats, and 1.9 and 2 carats. Couples on a budget should stay just under the half-carat mark, she says.