Chemical weathering alters the mineral makeup of rocks. It involves chemical reactions that break down the original minerals, often forming new minerals. Here's why:

* Dissolution: Water can dissolve minerals like calcite in limestone, removing them from the rock.

* Hydrolysis: Water reacts with minerals, altering their chemical composition. For example, feldspar can be broken down into clay minerals.

* Oxidation: Oxygen reacts with minerals, often creating iron oxides (rust) that are different from the original minerals.

Therefore, chemical weathering changes the mineral composition of rocks, not just breaking them down into smaller pieces.