I'll look into it, Goran. I think I remember there being a way to mod it, even in earlier versions.
Ieb: I have no idea, but it'd be great if there was. Possibly some kind of acid reaction? Vinegar + Stone = Sand? With vinegar maybe being something an alchemist could manufacture from any alchohol type.
One partial solution is to simply expand the uses for stone we already have. There are a lot of
stones, and even some ores, that we don't currently have a use for.
For instance, I'm always finding cobaltite on my map. Cinnabar and nickel too, frequently. The mod planned for this thread will have a handful of advanced steel reactions that use them.
Zinc and lead could also be more useful.
Orpiment could be used as a poison, or in tanning, or pigments if we ever get painting. Lots of stones are used as ingredients in paint, and this might concievably become a strong point of trade between dwarfs and humans, someday.
Stones like rocksalt and saltpeter could have uses in medicine and food-preservation, while microcline, and other feldspars, could be very useful for making ceramics/pottery.
Another item that would be nice to have would be cement. If we could mix stone with cement, and form a substance that Building Destroyer critters couldn't tear down, that might be really useful.
Not sure at all that any of this can be modding in yet, though.
Another partial solution is to add more useful types of stone into the game. Different types of coal, more ores, etc.