I forget where I got the silky sand, but I was in heart of the mists when I got it. It is a stack of 18, and when I double click it to “sift through it” it doesn’t consume the sand, doesn’t give the geodes I’m supposedly getting but does give me the coarse sand. I tabbed out of the window, logged into here, then I went to the trading post with my 19 coarse sand, didn’t sell it, but after exiting that the stack was consumed and is now at 8 instead of 18. I don’t think I could’ve had 200+ silky sand, so it was likely not a display error. As far as I can tell, the 19 coarse sand yielded acts like regular coarse sand, not disappearing when I move it or anything like that.