This report presents a project that focuses on the assessment of mechanical durability properties using quantitative microscopy. The project was financed by SGU under grant 03-1174/98. The aim has been to develop methods for assessment and presentation of rock quality data. Both optical and SEM/BSE microscopy were applied and combined with computerised image analysis and manual methods for the quantitative analysis. The first part of the project was to produce a literature overview of image analysis as applied to rock materials. A method for assessment of resistance to fragmentation of granitic rocks comparable with the Los Angeles test has been developed. By means of a quantitative description of foliation using a foliation index, FIX, it is possible to assess the potential length-thickness ratio of the crushed aggregate. Methods developed in the main part of the project have been applied in related areas. These include crack initiation and propagation under cyclic loading and cyclic thermal stress.