sapphire

(noun) a precious transparent stone of rich blue corundum valued as a gemstone.

(noun) a transparent piece of sapphire that has been cut and polished and is valued as a precious gem.

(noun) a light shade of blue. Synonyms: azure, cerulean, lazuline, sky-blue.

(adj) of something having the color of a blue sapphire. Example: "Sapphire eyes."