Welcome to Librarium Online!
I was just wondering who adds random crystals to their necron bases like games workshop has in the codex. In the codex that only have crystals on the bases of necron warriors, flayed ones, wraiths, lord, and the deceiver. I have put random crystals from sprues on one or 2 of my smaller squad models (ie squads of 10) and anywhere from 4-5 on larger squads (ie warriors). But i haven't tried to place them to the point where they looked spammed across my army. I chose to paint my crystals with a scab red base, blood red highlights, followed by several light coats of baal red washes, as opposed to dark angels green with snot green highlights.