Marquise cut

A marquise is long, wide in the middle and pointed at both ends, with brilliant-style facets. Another name for it is navette, which means "little ship" in Old French, and the shape does look like a boat. GIA dates the cut to France in the 1740s and says legend has it that it was named for the Marquise de Pompadour, a mistress of King Louis XV, because its outline resembled her mouth. A version in the trade says the king himself commissioned the design. Treat both as stories, not documented facts.

GIA calls every shape except the standard round a fancy shape, and gives an overall cut grade only to round brilliants. So a marquise is judged by eye, with help from its polish and symmetry grades. The pear cut is its closest relative.

Divide the length by the width, both in millimetres on the report. GIA puts the standard marquise at about twice as long as it is wide, a 2:1 ratio, and says the marquises submitted to its lab most commonly range from 1.6:1 to 2.2:1. A 12 mm by 6 mm stone is exactly 2:1.

A lower ratio looks fuller and closer to an oval. A higher ratio is slimmer and more dramatic, and it leaves the points longer and more exposed. Unlike with some shapes there is no single correct number, so pick the outline you like on a hand.

A marquise looks larger face-up than a round diamond of the same weight, and it can make fingers look longer and more slender. That makes it worth a look if carat weight is the limit. Check the girdle too. An overly thick girdle can make a diamond heavier than its face-up appearance warrants, while a sufficiently thick one reduces the risk of damage.

Many brilliant-cut marquises show a bow-tie effect, a dark shadow across the width. GIA makes a point that surprises people: stones without a bow-tie usually lack brightness and tend to look dull. You are looking for a shadow that is modest and soft, not for its complete absence. Symmetry is the other thing to inspect. Each half should be a mirror image of the other, and GIA grades symmetry from Excellent to Poor on its reports.

The length and the points make a marquise more likely to chip than a rounded shape, and secure settings such as V-prongs are essential, and some cutters use French tips to make the points more durable. A V-prong wraps the tip in two arms, so it covers the point from both sides. Ask where the metal will sit at both ends before you approve a design, and check that the stone is not left loose between prongs.

A prong setting is the setting GIA names for this, and it can be a solitaire or sit among smaller stones. Because the points are the vulnerable part, look at them under a loupe or in good light for inclusions or small nicks before you buy, and check them again when the ring comes back from any repair.

A marquise suits you if you want maximum visible size for the weight and are comfortable with a sharper outline. It is less forgiving if you work with your hands a lot, since the points are exposed to knocks. Compare two or three of similar weight and check each one for the bow-tie, the points and the symmetry rather than relying on the numbers alone.

The diamond shapes guide compares the main outlines. The engagement ring collection shows finished rings, and the design studio lets you note a marquise and how you want the tips protected. Custom engagement rings at Diamond Bros start with a showroom or video appointment, and the showrooms page lists locations.