Natural diatomite rocks are investigated. Their structure, mineralogical specifics, chemical composition, and phase transformation under thermal treatment are considered. It is demonstrated that diatomite rock is a promising material for enameling production.Diatomite rock is a loose, earthy or loosely cemented porous and lightweight rock of sedimentary origin, mainly formed by fragments of armor (skeletons) of diatom algae: diatomea and radiolaria. Diatomite is a microscopic singlecell diatom alga whose size ranges from 0.75 to 1500 mm; sometimes this rock is called infusorial earth, kieselghur, or mountain meal. The main components of the siliceous armor are silica hydrates of a different degree of water content (opals) SiO 2 × nH 2 O. Diatomite rock belongs to the group of silica-bearing materials. It analysis for the purpose of using it in the production of enamel frits is of interest in the context of the integrated application of local mineral materials and also in view of nsufficient knowledge of its technological properties.The Sverdlovsk Region has substantial resources of silica-bearing materials in the form of diatomite, tripolite, and opoka bedded at a small depth.We have investigated natural rock samples from the quarries of the Irbitskii and Kamyshlovskii Building Material Works. We have studied the structure, mineralogical specifics, and phase transformation in these rocks under thermal treatment ranging from room temperature to the melting point.Irbitskii diatomite is a yellowish-gray and Kamyshlovskii is a greenish-gray sedimentary rock whose main component is amorphous SiO 2 (70 -80%). The study of the physicomechanical properties of these rocks yielded the following data: their volume weight in lumps is within 500 -700 kg/m 3 , their porosity varies from 80 to 90%, the natural moisture is 7 -10%, their milling fineness (residue on a No. 008 sieve) is 9 -10%, and their specific surface area is 3800 cm 2 /g, which corresponds to a finely dispersed lightweight porous structure.A study of the granulometric composition of diatomite shows that the dustlike fraction (particle size 0.060 -0.005 mm) has up to 75% particles and the content of the sand fraction (particle size 1.00 -0.06 mm) is around 20%, and that of the argillaceous fraction (particle size below 0.005 mm) is around 5%. Based on these data, the diatomites considered can be attributed to the group of silty sandy loam, according to Okhotin's classification.To determine the mineral composition of Irbitskii diatomite rock, we performed x-ray phase analysis. A halo was identified in the range of small and medium angles, which points to a high degree of amorphousness of the main components of the rock. This conclusion is corroborated by the shape of the diffraction reflections; they have a blurred maximum and in some cases the half-width of a reflection is commensurate with its height. The main crystal phase is b-quartz, whose crystal lattice has the following typical diffraction reflections (d = 0.443, 0.034, and 0.181 nm).The average composit...

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