ultramarine

adj

1. (archaic)Beyond the sea.

   “[I]n England we ſhall never be taught to look upon the annihilation of our trade, the ruin of our credit, the defeat of our armies, and the loſs of our ultramarine dominions (whatever the author may think of them), to be the high road to proſperity and greatneſs.”

2. Of a brilliant dark blue or slightly purplish color like that of the pigment (noun sense 1).

noun

1. (countable, uncountable)In full ultramarine blue: a brilliant blue pigment traditionally made from ground-up lapis lazuli, and now usually either extracted from mineral deposits or made synthetically.
2. (countable, uncountable)A brilliant dark blue or slightly purplish colour like that of the pigment.

   “The atmosphere beneath is languorous, and is so tinged with azure that what artists call the middle distance partakes also of that hue, while the horizon beyond is of the deepest ultramarine.”