The article presents the statistical methods developed by the authors for the description of petrographic structures and textures. To display the statistics of binary and ternary intergrain contacts detected in thin sections, diagrams of a new type are proposed – barycentric triangle (p_ii, p_ij, p_jj) and tetrahedron (p_iii, p_iij, p_ijj, p_jjj). Both show the location of the Hardy-Weinberg equilibrium line, which characterizes massive rock textures. Computational procedures and results are demonstrated using the example of amphibolites of Vichennaya Luda and Sidorov islands (Keretsky Archipelago, White Sea).