I asked a science teacher at school and found the answer I was looking for.
I previously stated that I had experienced a very odd thing at the pug mill, in the blend of mixing, I found a chunk of clay that was ice cold (i.e. none of the obvious things applied, clay coming from an outside source...).
I was looking for a response along the lines of some sort of chemical reaction, similar to the clay heating up due to fiction.
I explained the circumstances of what i was doing, mixing clay, and that i reached to dislodge a chunk of clay that was stuck on the auger blade, and was shocked to find that the clay ice cold amongst a body of luke warm clay.
The teacher explained that it sounded like an exothermic (exit) endothermic (enter) reaction.
That because the clay I was reaching for, was stuck to a blade and not moving amongst the rest of the moving particles, it could not react to the fiction of the rest of the clay.
And so it reacted in the opposite manner, exothermically.
Because that chunk of clay could not mix and warm through fiction, the greater mass of clay endothermically pulled the stuck chunk of clays warmth into its own body as the stuck chunk pushed its own warmth exothermically into the blending clay body.
And so, by comparison, the difference in temperature was quite dramatic.
