The paper includes a cracking process analysis of Krosno sandstones from the Górka-Mucharz quarry (Beskid Mały Mts.) based on fracture toughness tests by the chevron bend method. The analysed rock material features the internal structure: a laminar location of mineral components and directional location of non-isometric grains. These features impact the anisotropy of various geomechanical properties of these rocks such as fracture toughness or compressive strength, and are the reason for a varied crack development as well. The test results and cracking process characteristic regard three orthogonal measuring directions as adopted in relation to the rock material structure and texture features
described in this paper. As concluded from the interpretation of load and strain increments recorded during the test, the cracking process is at its quietest when in the same direction as the layer direction, whereas, the most rapid failure character is observed in the direction perpendicular to the layer direction and to the longer mineral grain axis.

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