I made a discovery.
Everyone knows that clay is unlimited. I started playing a bit around and noticed that if you change FIRED_MAT on the clay, it is not accepted as clay anymore. Logically, this should mean that all inorganics with FIRED_MAT would be accepted as clay. This is correct. They also need the soil tag. It would look like this:
[SOIL][MATERIAL_REACTION_PRODUCT:FIRED_MAT:INORGANIC:WHATEVER]
If you add this to any inorganic, lets say gabbro and granite, then they wont leave any boulders when mined, but unlimited gabbro/granite boulders can be collected.
Now, if you add [ITEM_SYMBOL:''] to it, you can collect items that look very differently, it does not have to be a boulder.
If you add ENVIMONMENT_SPEC:INORGANIC:WHATEVER:CLUSTERONE:, then you can have rare finds while mining, that give you access to a specific, unlimited material.
To make it even more interesting, lets assume the inorganic mat does boil away at room temperature. While being dug, nothing happens, because soil doesnt leave boulders to boil away. But when collected, it would result in a cloud of gas affecting the worker.
Now all this modded stuff does not quite fit clay collection, so insolors string dump replacer can rename the hardcoded clay oven, or just the reaction to something else. "Collect clay" could be anything you want. Same goes for the clay-zone.
My line of thought: "You have struck a Place of Power!"... lets go to my workshop with the custom name, and select the "Empower a dwarf" reaction. Needs an active "Powered Zone". Dwarf runs to the single Place of Power you found, is affected by the syndrome adding temporary boosts. All kinds of magical gems could be hidden away like this, founding an entiry upgrade system.
I for example have a rare "Breath of Armok" gem, which gives the miner that digs it a temporary syndrome, the "Blessing of Armok", giving him super speed. With this system, these could be unlimited speed-boost stations. I am sure Total Conversions can make some use of this. Or you could use a vein instead of a single tile, call it "ley line".
I will use a tamer version of this idea, for two new inorganics in MasterworkDF. Dirt and Peat.
Peat already exists and contains clusters of compact peat that can be mined and burned for fuel. I think changing the system to a slow, labor-intensive, but unlimited source of "collect peat", which is then compressed and burned for fuel, would be a nice change.
Dirt would be simply used for my decorational plant workshops, like potted plants and patches of grass, as well as build-mat, for example for a herb-garden. Or used to cultivate a plant in a reaction. Dirt + Seed + Fertilizer = Plant.
Anyway, I just thought I share this with everyone, because it was clearly new for me. Evaporating clay-collection zones that give syndromes...
The very same could be done with sand I assume, but that would require bags.