A scanning electron microscope has been used to observe the microfabric changes in granite that are brought about by weathering. The initial ingress of weathering agencies occurs along primary cracks and pores and open cleavages and results in decomposition and solution along structurally controlled planes in feldspars, the decomposition and expansion of the biotite lattice, and solution and microfracturing of quartz. In terms of the fundamental material nature of weathered granite, the initial stages of weathering are dominated by the opening of grain boundaries, microfracturing and the development of an intragranular porosity in feldspars. The later stages of weathering are dominated by the variable nature of the clay weathering product.