a tone that's too dark may obscure the blue hue. The ideal tone for sapphire gemstone will fall somewhere in the middle of the light and dark spectrum. And when it comes to saturation, the best sapphires typically have rich, constant, vibrant colors devoid of brown or gray patches. Royal blue, also called cornflower blue, is the ideal shade of sapphire if you are considering engagement rings with sapphire . Cut The most ideal way to bring out sapphire's best features and show off the stone's brilliance and shine is by cutting it symmetrically . While there is no specific 'best' cut for this gemstone, round, cushion, and emerald are the most popular cuts. You can always pick one that suits your preference and that of your fiancé.