Aim of the study is to compare the morphology of inclusions in magnesium alloy, investigated by both computed micro-tomography and light microscopy. Precipitates of denser material are found. The information of the light microscopic studies alone is by far insufficient to conclude on their three-dimensional shape. In contrast, the tomography reveals the full topology in all dimensions. The described inclusions are flake-like and can extend with high aspect ration into one, two or three dimensions.