Understand weight before comparing size
A carat is a unit of weight: one carat equals 0.20 grams. Two diamonds of the same carat weight can look different in size because their shapes and proportions differ.
Center stone and total weight
“ct” may describe one stone; “ctw” or “total carat weight” describes the combined weight of several stones. Always ask which measurement appears in a listing. A ring with 1.00 ctw does not necessarily have a 1.00 ct center diamond.
Compare visible measurements
Review length, width and depth in millimeters, together with the design. A stone's face-up appearance, setting height and band width all affect the impression when worn. Ask to see the proportions on a hand or in a suitable scale reference.
Balance the purchase
Set a comfortable total budget for the stone, setting and any applicable charges. Compare nearby weights with attention to appearance and the complete quotation, rather than selecting by a single number.
Find a weight and proportion that suit you.