On this small island in Liyue, there is a seal blocking a hole where materials such as Violetgrass can be seen.
There is a tablet in front of the seal, presumably a puzzle of sorts to solve to open the seal. But I haven't found any solution that has worked.
How do you get past the seal in Sal Terrae?
As of 1.1 version this location is now unlocked during one of story quests:
Zhongli's Historia Antiqua Chapter, Act I: Sal Flore
It seems from this article that it's not currently possible without glitching out of the map.
all of your troubles are in vain, as currently, this barrier is not accessible in version 1.0 of the game. However, it may become a quest in update 1.1, but no one is sure at this present time.
There is a map breaking glitch which allows you to fly and climb down into the area to collect the bits and bobs in there.
