Abstract In this paper, we discuss the effects of sintering temperature on the properties of diatomite ceramic biomaterials. Diatomite from Cyclostephanos sp. was sintered at 950 °C, 1100 °C, and 1250 °C to evaluate how thermally driven phase transitions, pore architectures, and wetting behaviour govern its application for cell culturing and tissue scaffolding. X-ray diffraction revealed that sintering at 1100 °C and 1250 °C produced predominantly β−cristobalite ceramics, whereas 950 °C samples retained substantial amorphous silica, leading to rapid disintegration in aqueous media and exclusion from biological testing. Model endothelial cells (MDCK-2) exhibited good adhesion and proliferation on both 1100 °C and 1250 °C ceramics, with significantly higher cell densities observed on 1250 °C samples from days 6-8. Image-based pore analyses revealed that 1250 °C sintering generated larger and more numerous micron-scale pores, as well as a 1.18-fold increase in water imbibition velocity, suggesting enhanced early-stage cell attachment via improved capillarity and surface accessibility. Both materials have shown similar efficacy as bioplatforms for pre-osteoblasts (MC3T3-E1) differentiation and mineral deposits formation. Collectively, the results show that sintering temperature critically determines crystalline phase, mechanical stability, and pore morphology, which in turn affects cell proliferation rate. Keywords: Diatomite ceramics, Sintering temperature, β-cristobalite, Pore architecture, Osteoblast differentiation