The excavations in Iznik, which aim to present the history and cultural heritage of the city, had started in 1969 in the sites of Orhan İmaret and its Bath (Turkish Hamam) and continued for kilns. We present here the first on-site, non-invasive analyses performed with portable XRF (pXRF) instrument in twenty-five excavated tiles both glazed and unglazed, and two residue materials of the kiln. The shards studied were attributed to the productions from 14th-to 17th-centuries. Comparison is made between the discussion of characteristic elemental composition ratio selected from ceramic technology criteria and PCA/Euclidian diagram analyse. Three groups of body composition were evidenced: 1-rich in clay, poor in quartz and 2-poor in clay, rich in quartz as previously demonstrated and linked to Timurids heritage and characteristic of Iznik potter innovation, respectively; and 3-a new group, a mixture of quartz, clay, and chalk. We encountered three different glazing technologies: Sn-rich, Sn-medium and Sn-poor glazes. The amount of tin oxide in the glaze decreases by centuries. Besides, two different types of fluxes used in the glaze, some containing only potassium, and the others having potassium and calcium. The decors, which were investigated in this study were blue, turquoise, green, red colours, and black lines. Three mixtures of cobalt ores were determined. The blue pigments from European cobalt sources are a mixture of Co-Ni-Fe-As. The Chinese-like source was also determined in some of the tiles without arsenic and the ratio of Mn versus Co > 1. The third cobalt source contains Mn/Co < 1 without arsenic. Most of the red colours contains iron but some with a mixture of copper and iron consistent with the use of the bornite (Cu 5 FeS 4) mineral from Anatolian (Turkey) mining, not documented before in Iznik decors. Spinel or chromite-based pigments were used in the drawings of black lines. Green areas contain copper or chrome containing pigments. The addition of copper lead to turquoise colour. ajouter figure sur glaze ou cobalt