1 Carat Marquise Diamonds

No shape gives more diamond to the eye per carat than the marquise. A one carat marquise runs about 10 by 5 mm against 6.5 mm for a round of the same weight — nearly twice the length, and it makes the finger look longer while it does so.

Symmetry is the first thing to check, before colour or clarity. The two points must sit on a single axis and the two halves must mirror each other; when they do not, the eye catches it immediately even though no grade on the report will say so. Read the symmetry grade, then confirm it in the 360° view.

The classic ratio runs 1.85 to 2.10. Below that the stone looks stubby, above it the tips grow fragile — and the tips are the thinnest part of any diamond. A setting with V-prongs covering both points is protection, not decoration, and at one carat it costs nothing extra to specify.