0.66ct D SI2 Marquise Natural Diamond

About this 0.66ct natural marquise diamond

This 0.66ct natural marquise sits in the half to three-quarter carat band, graded D colour (colourless) and SI2 clarity (slightly-included), with a very-good cut grade stated by the retailer rather than the lab and certified by GIA 5181153321. Listed at 5 retailers as of October 28, 2026, with a relatively tight 9% spread, which is unusual at this carat range and suggests competitive pricing across the listings. Cut grade matters more than carat or clarity for visible brilliance. If you can shift budget toward an Excellent or Ideal cut, do it before chasing higher colour or clarity.