In ceramics, raw material chemistry is expressed as analyses. This is in contrast to fired glaze chemistries which are expressed as formulas.
Glaze chemistry is the study of how the oxide chemistry of glazes relates to the way they fire. It accounts for color, surface, hardness, texturem, melting temperature, thermal expansion, etc.
The vast majority of materials used in ceramics are insoluble. But many still present hazards. And you can add hazards (to you and customers of your ware) by the way you use them. Still, there is a need to be realistic about it.
What is clay? How is it different that regular dirt? For ceramics, the answer lies on the microscopic level with the particle shape, size and how the surfaces interact with water.