I did the new Corrosive roll, got a neat random name, Gaia I, so keeping it, off Alcyon. Lower count than others but appears to have some good spots.
I’ve found on emerald, you can do good on it and it is a lot more profitable overall on other stuff if you work along the amethyst/emerald hotspot line under larger water bodies on Corrosives. Amethyst close to shore, emerald further out, see decent emerald there on the outer edges of the emerald spots. I’ve got a good emerald planet, Stellamaris VI, but you aren’t going to get much else valuable but the emerald in the hotspots there.