Scanning electron micrograph of a steel fracture surface. This sample failed in a brittle intergranular manner (along grain boundaries), as evidenced by the "rock candy" appearance of the fracture.

SEM micrograph of a fracture surface in an cast zinc aluminum alloy. The sample failed in a brittle transgranular manner. Note the flat surfaces in the shape of grains. The microstructure of this sample is lamellar, and the grains of this sample fractured along the layered phase boundaries. 600X