The paper presents results of investigations aimed at determining the structure of low-temperature tridymite in refractory silica materials. In the initial phase of works, the literature and Internet databases containing structural data of crystalline compounds were reviewed in search of a model of tridymite structure which best fits the one forming in silica materials. The results of reviewing the models of polymorphous tridymite forms which are available in the world literature have been verified by Rietveld method, using a sample of silica material that contained tridymite without cristobalite and residual quartz. On the basis of analyses it was found that tridymite in refractory silica materials occurs in a form of two low-temperature polymorphous forms C1 and F1, instead of one form – Cc, as it was assumed before. The developed model has been used in a quantitative analysis (Rietvield method) of phase composition of several silica refractories.