Investigated Latvian Quaternary and Devonian clays are suitable for obtaining of honeycomb ceramic (expanded clay ceramic). Technological possibility to obtain expanded clay ceramic is different by considering of different chemical composition of investigated raw clays. Content of iron and calcium oxides is more significant. Reduction process is possible thanks content of Fe2O3, but in addition presence of carbon containing composition intensify this process. The main factor for determination of technological parameters is the high temperature phases which form in clay by fast firing at fixed temperature. Viscosity of these high temperature phases has significant role because provide pores formation in result of reduction Fe2O3 and formation of CO and maintenance of granules shell. More suitable for production of expanded clay ceramic are clays in which forms anorthite at high temperature. In result of these investigations there are established that Quaternary clay of deposit Apriki is the best for production of honeycomb ceramic. By slow heating to 6000C of clay by additive of 2 wt% of oil and by following displacement at temperature 11500C the expanding coefficient is the largest.