The microfabric characteristics and mineralogical composition of rocks are of fundamental importance in understanding their engineering behavior in various construction applications. Here, we quantify the petrographic characteristics of a number of mafic rock samples, collected from ophiolite complexes in Greece, aiming to elucidate their mechanical behavior when used as aggregate materials. The microfabric parameters of these samples were quantified by measuring the perimeter between the different mineral phases using scanning electron microscopy in combination with image analysis, while their mineralogical composition was quantified with a polarizing microscope using the point-counting method. The mechanical properties of the samples were assessed through a variety of laboratory tests, which included the Los Angeles abrasion test, the aggregate impact value, the micro-Deval test, the Schmidt hammer value, the uniaxial compressive strength, and the point load strength index. The correlations obtained between the microfabric-mineralogical data and the mechanical parameters demonstrate that a quantitative petrographic characterization of aggregate materials could substantially contribute to a deeper understanding of their strength properties, thereby allowing a reliable estimation of their in-service performance.