The many-*fauceted* scarlet emerald... which no doubt has many little taps stuck into its surface?

Coruscating is, as I suspect you already know, one of the adjectives Doc Smith used over and over again (along with polychromatic) to describe lenses. In later years he threw in an occassional "scintillating" but by that time "coruscating polychromatic lens of the Galactic Patrol" was practically a trademark phrase. I suspect he used it that way deliberately.