Chemical Weathering

Alters the internal structures of minerals by removing or adding elements
Most important agent is water
Oxygen dissolved in water oxidizes materials
Carbon dioxide (CO2) dissolved in water forms carbonic acid and alters the material

Weathering of granite
Weathering of potassium feldspar produces clay minerals, soluble salt (potassium bicarbonate), and silica in solution
Quartz remains substantially unaltered
Weathering of silicate minerals produces insoluble iron oxides and clay minerals

Spheroidal Weathering
Generates rounded rocks
Weathering works inward from exposed surfaces