Final answer:
The described process where minerals dissolved by water crystallize within rock formations is known as crystallization. This process forms minerals such as calcite and aragonite in natural settings like caves, and is related to recrystallization, where dissolved solutes return to a solid state within a saturated solution.
Step-by-step explanation:
The process described by the student, where water seeps into rock cracks and dissolves minerals, then transports the solution through cracks and eventually concentrates into large crystals, is known as crystallization. This chemical process can occur within nature when rainwater, which is slightly acidic due to dissolved carbon dioxide, reacts with rocks such as limestone, dissolving calcium carbonate and forming ions.
These ions are then carried by the water through cracks and fissures until they reach areas like cave ceilings. Here, water droplets can linger, allowing the carbon dioxide to escape, raising the pH, and prompting the ions to recombine and form solid minerals such as calcite, aragonite, stalactite, and stalagmite.
Recrystallization is a related process where the dissolved solute returns to the solid state, especially in a saturated solution where dissolution and recrystallization reach an equilibrium. Additionally, processes like weathering and erosion contribute to the increased content of dissolved minerals in water, which can later be deposited as solids in various geological formations such as evaporites.