Does ceramic just naturally absorb heat much better / faster than unglazed quarry tiles, and pizza stones ?
It depends on a few things.
First, I'd consider unglazed quarry tiles, and pizza stones as ceramics as well, just with different properties.
The two that would seem to be the most important are heat capacity, and thermal conductivity.
Heat capacity is mostly a function of density, and is the amount of heat you can store. Thermal conductivity is a measurement of how fast (or slow) that heat is transfered. Corderite and Fused silica have relatively low heat capacity and thermal conductivity. Materials such as Mullite and Alumina have progressively higher heat capacity and thermal conductivity.
Fused silica, Mullite and Alumina are all variations of the same creature, with different quantities of Silica (SiO2 ) and Alumina (Al203)
Fused Silica is typically 70% Silica and 30% Alumina
Mullite is typically 35% Silica and 65% Alumina
Alumina is typically no more than 15% Silica and 85% or more alumina.
As the Alumina content increases, the heat capacity and thermal conductivity increase, as well as chemical resistance, also, the maximum use temperature increases, which will approach 3200F. BUT this come at a cost, both in terms of thermal shock resistance and dollars.
Typically I would recommend the material with the LEAST amount of Alumina that meets the rest of your needs.
Quarry tile and pizza stones (corderite I presume) contain silica and alumina, but also magnesium oxides, and higher levels of clay.
Magnesium oxides are great for resisting attack from molten stainless steel, but really add nothing to pizza making environment.
The more clay you have, the easier the part is to press (if your pressing parts), and handle in an unfired state, but it adds nothing to a part, in terns of thermal shock resistance or thermal conductivity.
How this helps a little, and doesn't make things more confusing.
I'll have our cad guy draw up one on Monday, but I'm thinking a box that is about 5" high 16.5" deep, and 17" wide.
Top and bottom will be 3/4" thick and the walls will be 1/2" thick.
This would give inside dimensions of 16" x 16" by 3.5"
One of the walls will be missing, so that pizza can be placed in the box to bake.
The bottom could be a separate piece for ease of cleaning, or to use as a baking stone for taller items.
To answer your original question, fused silica would have a far superior thermal shock resistance compared to quarry tile or corderite.
I will have some thermal cycling tests done next week, but I see no reason I wouldn't be able to heat these parts to 800F and then drop them in a bucket of cold water without having them break. I've had corderite pizza stones crack on me in the past when I've added cold wet dough to a hot stone.
Short of beating them with a hammer or dropping them onto stone or concrete, fused silica parts should last indefinitely.