It is often difficult to identify and quantify mineralogical heterogeneities on the centimetre to metre scale by optical means, when these heterogeneities have apparently similar colours. Therefore, a general image processing workflow combined with mineralogical analytical methods is presented by using contact-free hyperspectral imaging techniques on a mudstone concretion. The application of spectral algorithms reveals a distinct texture in a visually homogeneous black rock. The pattern is confirmed by optical and electron microscopy as well as X-ray diffraction, showing a layered texture of varying amounts of siderite and clay minerals. The rapid and contact-free visualisation of rock anisotropies such as mineralogical heterogeneities in overall homogeneous rocks may thus enable a better prediction of mechanical and petrophysical heterogeneities on mm- to 100 m scale.