Marquise Lab-Grown Diamond 6×3 mm, Loose

A marquise lab-grown diamond, 6 x 3 mm, D to F color, VVS clarity, sold individually. A boat shape, pointed at both ends.

The shape with the largest face for its weight

A marquise spreads its weight along its length and is very shallow, so of all shapes it gives the largest face area for the same weight. In other words, for the same money, a marquise looks biggest.

That's its strength and also the trade-off: being shallow, light passing through it is bent less, so it sparkles noticeably less than a round. You trade brilliance for size.

Two points, not one

Unlike a pear with one tip, a marquise is pointed at both ends. That means twice as many places likely to chip, and both need fully covering prongs. This is a shape where skimping on prongs ruins the stone.

The 6 x 3 mm size is usually used as side stones flanking a center, or arranged in petal and leaf patterns. Boat shapes arranged in a circle create a very distinctive pattern that round stones can't.

The bow-tie in the middle

Because a marquise is elongated, almost every one has a dark bow-tie shape across the middle, called a bowtie. Skillfully cut, it's faint; poorly cut, it becomes a clear dark band.

This isn't recorded on paper and can't be seen in photos. If you're using a marquise as the main feature, look at the stone in person in ordinary light.

Care

Wash with warm water and a soft brush, paying attention to both points and the underside in the middle. Take it off for manual work.

Have the prongs at both ends checked every few months. On this shape, a loose prong at one end lets the stone twist off its axis, which shows at once.