The study analyzes the existing methods for assessing the suitability of clay raw materials for the production of architectural and construction ceramics and substantiates the need for their improvement in the direction of developing an indicator based on an analysis of the mineral composition of clays. Using the compositions of the kaolinite – montmorillonite – hydromica – quartz system, which simulate the composition of polymineral clays, the effect of clay-forming minerals and quartz impurities on the properties of the clinker ceramic materials has been established. It has been determined that the montmorillonite component of the compositions has a positive effect on the water absorption of materials, and kaolinite produces a favourable effect on the mechanical strength and frost resistance. The increase in the content of quartz in the composition of compositions from 30 % to 50 % leads to an increase in water absorption of materials, reducing their strength and frost resistance to a level unacceptable for ceramic clinker. It has been established that to obtain clinker ceramics, the quartz content in the compositions cannot exceed 40 %. A diagram of the mineral composition was developed, clearly illustrating the ratios of the main rock-forming minerals in clays with a quartz content of 30 % and 40 %, acceptable for the production of modern clinker products. The diagram shows areas of the mineral composition of clays suitable for the production of facing, paving and road clinker of the M200–300 grades and road clinker of the M400 grade at a firing temperature of 1,100 °С. The diagram of the mineral composition complements the existing indicators of the suitability of clay raw materials for the production of architectural and construction ceramics and can serve as an additional criterion for assessing their technological quality. The diagram can be used to analyze the suitability of clays for the production of ceramic clinker, provided that only the mineral composition of clays is determined without establishing their chemical and particle size distribution