Analysis of the geometry of soil grains for four types of soil abrasive mass was presented. Assessment of the geometry was carried out with the use of a stereometric microscope with the use of Motic Images Plus 2.0 programme. External radius of the circle inscribed in the contour line of the abrasive grain, internal radius of the circle inscribed in the contour of a grain, fields of protrusions of irregular figures of a grain and circumferences of protrusions of irregular figures were assessed. Soil fractions of gravel, sand and loam and dust in sandy and clay soils were investigated. The obtained results and statistical calculations enabled determination of significant differences in the geometry of abrasive mass of grains and their variable shape in particular soils. The smallest differences of fractions were determined for fraction of dust and loam (at the maximum 28%), whereas the biggest for sand fractions up to 79%. It proves necessary to include also geometry of soil grains in the selection process of properties of the working element surface layer to a specific type of the processed soil, next to the granulometric composition and reaction of soil. The objective of the paper was to assess geometry of grains of gravel fraction, sand and dust along with loam, which compose the selected types of soil abrasive mass.