The general thing that is happening is this: water allows the sugar molecules to separate without paying as large an energy penalty. This means the higher entropy of disordered sugar molecules allows that energy penalty to be overcome at lower temperature (and/or higher concentration, which reduces the entropy increase.)
The same thing is happening with water and rock, if not by exactly the same mechanism. Water reduces the energy cost of breaking bonds in the rock (covalent Si-O bonds, not hydrogen bonds).
Adding water to rocks does result in a solution. Rock is very slightly soluble in water. It's just that at normal temperature and pressure the solution is extremely dilute. This is because the energy penalty is so high that a very large entropy increase is needed to overcome it, and the entropy is logarithmic in dilution. Raise the temperature a bit and the solution becomes more concentrated. This is how quartz is deposited to grow artificial crystals for electronics: it goes into solution in hot, pressurized water and is deposited on seed crystals. This also happens naturally with various minerals (including quartz.)