These are tests of some of my local clays.
The red clay is my reclaim. I may have gotten lucky with this batch as there is a bit of kiln wash stuck to the bottom so it maybe vitrified. That usually only happens when the clay is close to maturity and starting to soften.
The brown clay is what I call Sandstone Clay with 15% added nepheline syenite.
The flat tiles are my light colored clay with 10% and 15% nepheline syenite. The small broken piece is the light colored clay mixed with 20% marl. I really over estimated that one cause the tile is stuck firmly to my shelf. I’m going to have to chisel it off.