This paper mainly dealt with the geochemistry, mineralogy and genesis of the bauxite deposits of Ratnagiri district of Maharashtra. The bauxite deposit occurring at an elevation of 320 m from the mean sea level in the Konkan tract with a step-wise fall in the altitude from east to west. Regolith occurs mainly over the Deccan basalts and forms characteristic weathering profiles with distinct petro-mineralogical features. A simple geochemical balance of lateritization processes governing the development of several tens of meters of weathering profiles overlain by duricrust is estimated on the basis of detailed mineralogical and geochemical data.

The weathering mantle at the study area is composed of different weathering layers described from the base to the top of vertical profiles. These profiles are visible into the saprolith, pedolith, and in variably a topmost lateritic duricrust. Based on the textural and mineralogical studies, the saprolith is further differentiated into sap rock and saprolite where
as pedolith is sub divided in to plasmic and mottled zones. The appearance of sap rock is not uniform throughout but it is observed in the Gothane-Vikhare profile where, as a well developed saprolite horizon is encountered at Hativale profile.

Primitive stage of alteration of primary minerals is observed well within the sap rock where as the profuse neo-mineralization is depicted by the saprolite zone. Pedolith part is characterized by the absence of relict minerals and it commences with an aluminous or ferruginous plasmic zone. Gibbsite is the main component of the bauxite zone with minor amount of goethite or limonite. The main component of the laterite zone is gibbsite with subordinate amount of goethite. Thelithological gradation from bed rock upwards to the duricrust is very well preserved in the surrounding area. Geochemical data of major oxides of the profile samples reveals that the rocks of the area are mainly composed of 81.23 to 99.44 % major oxides. The alumina content varies from 40.35 and 49.45% in bauxites and 25.72 to 33.84% in laterites where as it is very low in Deccan basalt which varies from 14.9 to 16.07%. Fe2O3 content varies in all the profiles which is highest at the lateritic zone (45.52-40.05-37.45%) and lower at the Deccan basalt (11.92-12.29-12.37%). The LOI is directly proportional to the alumina content and inversely proportional to the Fe2O3 content.