An apparatus for analysing a sample of granular material, such as soil, is described. An elongated housing has a channel extending therethrough to define an optical path. A cavity is defined within the top of the housing to receive the sample, and a transparent sample-receiving surface is disposed within the cavity at a first elevation from the bottom of the housing. A lens assembly is positioned within the optical path at a second, lower, elevation. The lens assembly magnifies an image formed by light beams reflected by or transmitted through the sample. An image capturing device is disposed across the optical path at a third elevation that is lower than the second elevation. The image capturing device is thus lower than both the lens assembly and the transparent sample-receiving surface. A light source is mounted within the housing to emit light toward the sample-receiving surface.