A facile and sensitive quantitative visual analytical method has been developed for the determination of Al3+ in geological samples. The alumina (Al2O3) content in gibbsitic bauxite and related samples of geological origin is extracted in triple acidic medium. The sample solutions are purified and then subjected to quantitative thin layer chromatography (TLC) analysis. Combination of plain silica gel H and dilute aqueous solution of aluminon (0.005-0.50%) has been identified as the best chromatographic systems for the selective detection of Al3+. The important chromatographic parameters such as sample composition, pH effect, nature of adsorbent and mobile phase composition as well as detection limit are optimized in terms of spot size, colour stability and resolution of Al3+. The TLC chromatograms of Al3+ are quantitatively assessed by scanning densitometry and digital image analysis. Analytical potential of the optical quantitative methods have been verified for the quantitative TLC assessment of Al3+ in bauxite, soil, rock and aluminium spent potlining (SPL) samples with respect to the analogous wet analysis. Repeatability and reproducibility of the method are also evaluated under the optimized experimental conditions such as sample concentration, components and pH, slurry volume and layer thickness.