If you play on extinction break the trees with white leaves, they give blue crystilized sap which works like this. Becareful because corrupted creatures hurt. Would recommend going near the desert some because worst thing is corrupted rex
There’s a little “staircase” down to the bioluminescent on abberation (it’s the only land entrance that doesn’t require a jump, iirc) which is a transition zone. There’s a fair amount of blue gems for the taking. Be prepared to fight off various creatures on the way and while there (rock drakes, too).
how to get. go to abberation or a abb cave such as fjordurs abb cave. mine it then use the obelisk to item transfer (dont know what i mean? well there is a tab called items that you can put items into so you can acess them from ALL your single player maps, you can also do this with creatures that are on the terminal just note this will remove saddle and inv so maybe use cryo instead to keep saddle) then get this. you can also get gems from a roll rat. just fight it or run. simple.