Sri Lanka is known for different kind of iron-ore deposits in the Precambrian basement. Among them, hydrated iron ores are predominant in the south-west region. This study describes geochemistry, weathering, alteration and provenance of hydrated iron-ore deposit and examine different chemical processes associated iron-ore generation. Field surveys were carried out at forty four (44) localities around Dela and X-ray Fluorescence Spectroscopy (XRF) was used to obtain concentrations of forty (40) major and trace elements from ore samples. Selected samples were also analyzed by Fourier Transform Infra Red Spectrometer (FT1R) aiming at identification of weathering and alteration effects. The average concentration of Fe20:, in the deposit is 88 wt% indicating a high grade iron-ore. Conversely, all the other major oxides (MgO, ALOj, Si02, P20 5, MnO, CaO and Ti02) concentrations are not significant. Based on geochemical discrimination the deposit falls in to Phanerozoic iron stones indicating igneous intrutions to the Precambrian basement. The deposit can be conceded as detritus-free when" originated since minute concentrations of trace elements are reflected in the samples. Major oxides of the study show residual enrichment of Fe2Oj due to effective leaching of mobile phase. Lower abundances of immobile trace elements may reveal lack of commonly known heavy minerals within the iron bearing formation. The FTIR spectrum of the iron-ore samples clearly demarcate chemical weathering processes as imposed by the deposit such as formation of secondary'minerals (limonite), silicate oxidation and phosphorous decomposition.