Regarding: Echostone fragmenting

This is mostly guesswork based on what I've observed.

I went to fragment a lvl 10 blue echostone and it showed that I would get a finest echostone stimulant. So what you get back might also depend on the dungeon level since someone else said that 6~11 it was only fine....

Additionally since you can get a finest echostone stimulant at lvl 10 I believe there might be a series of potent stimulants at higher levels.

Does anyone know if echostones are limited to just one line?

You can place your current highest level stimulant in the fragment and it'll list the potential items you'll get. Grade 12 stone will list Finest echostone stimulant, ancient powder, and ????? which probably means the list of extra items

Level 8 for finest.

As well, the page mentions ancient powder but I haven't seen that show up as a result until 10.

better random stuff can be obtained from higher grades maybe?, i got 1 ancient golden crystal from a grade 25 silver echostone, i will keep fragmenting at that level to see what i can get.