'Blue' in the Bible

So I looked, and behold, an ashen (pale greenish gray) horse [like a corpse, representing death and pestilence]; and its rider’s name was Death; and Hades (the realm of the dead) was following with him. They were given authority and power over a fourth part of the earth, to kill with the sword and with famine and with plague (pestilence, disease) and by the wild beasts of the earth.

And this is how I saw the horses and their riders in my vision: the riders had breastplates [the color] of fire and of hyacinth (sapphire blue) and of brimstone (yellow); and the heads of the horses looked like the heads of lions; and from out of their mouths came fire and smoke and brimstone (burning sulfur).