When researching diamonds, be on the lookout for stones that register just under the benchmark carat weights such as 1/2 ct. 3/4 ct., 1 ct., etc. Diamonds that are just outside of the popular weights are often sold for less when compared to diamonds of full weight. For example, a .90 carat diamond will typically cost less on a price-per-carat basis than a full 1.00 carat diamond. To the naked eye, the difference is negligible. A smaller carat weight diamond may have a diameter equal to that of a higher carat weight diamond, being perceived as the same.
The most popular carat weights for diamonds are between one and two carats. If a diamond under .75 carats is a budget necessity, consider a marquise cut or princess cut, which appear larger than other shapes of equal carat weight, due to elongated cut or a broader table.