Not for absolutely every material, no. And you can definitely put sand into clay, but the question is what kind of sand? Sand has different compositions based on the parent rock.  When I was at NCECA in 2019, Rimas Visgirda gave a talk about his work, and a big part of that is different kinds of inclusions. He talks about coarse grades of feldspar and quartz, as well as using things like chicken grit and different kinds of sand. It’s not an exhaustive list, but it does talk about a few thin