Diaspore is an aluminum oxide hydroxide mineral (AlOOH) that occurs as a primary aluminium-bearing mineral in certain types of bauxite deposits, particularly those found in Turkey, China, Greece, and parts of the Middle East. Unlike gibbsite and boehmite, which are the more common aluminium hydroxide minerals in tropical and subtropical bauxite deposits, diaspore is the dominant aluminium mineral in diasporic or diaspore-rich bauxites. These deposits are typically formed by the weathering of metamorphic or sedimentary carbonate rocks and are associated with karst-related geological settings. Diaspore is considerably harder and more chemically stable than gibbsite, requiring more severe digestion conditions — higher temperatures and pressures — in the Bayer Process for alumina production. This makes diasporic bauxites more expensive and energy-intensive to process compared to gibbsite-bearing bauxites. Accurate identification of diaspore content in bauxite ore is therefore critical for process plant design, energy budgeting, and selecting appropriate operating conditions during alumina refining. Mineralogical analysis techniques such as X-ray diffraction (XRD) are routinely used to quantify diaspore in bauxite ore characterisation programs.
