I can't get the Thaumetic Sulphite!!!

I can't get the Thaumetic Sulphite and i tried to leave the area but that didn't work.
I tried to exit the game and i saw the Thaumetic Sulphite on the map but when i went closer it just dissapeared on the map and i couldn't interact with the container!!! :( pls help

Create a new instance. Ctrl+click the entrance.