Marquise is a football-shaped brilliant cut — pointed at both ends. It has the largest face-up size per carat of any shape: a 1.0ct marquise looks larger on the finger than a 1.0ct round, oval, or pear.
Pricing 20-25% below round. Combined with the size bonus, marquise is the cheapest way to get a "big-looking" diamond.
Two sharp points are vulnerable to chipping. Settings must protect them — V-prongs at both tips, bezel, or half-bezel.
Marquise has fallen out of fashion since the 1980s peak. Resale market is thinner than other shapes, so factor in 30-40% resale (vs 35-50% for round) if resale matters.