The word "carat" is taken from the carob seeds that people once used in ancient times to balance scales. So uniform in shape and weight are these little seeds that even today's sophisticated instruments cannot detect more than three one-thousandths of a difference between them. A carat is the unit weight by which diamonds are measured. One carat is equal to 200 milligrams or 0.2 grams. Size does matter! Differences in size are clearly visible, even to the untrained eye. Carat should not be confused with Karat, which is the method of determining the purity of gold. Large diamonds are rare and have a greater value per carat.
Deciding on a carat size means striking a balance between size and quality. If she prefers larger jewelry pieces, you can still buy her a large diamond by staying within your budget. Just choose one that is graded lower in color and clarity. Remember, that slender fingers made diamonds look bigger. If she has small fingers, a 1 carat diamond will look proportionately large and a larger stone may appear too big. The setting you choose should be made to fit the carat weight of the diamond.