Abstract In the Bygoo region of southern N.S.W. (Australia), the Ardlethan Granite is commonly deeply weathered and has sparse outcrop. It contains small, structurally controlled tin lodes and buried disseminated mineralization which is associated with intense alteration (silicification/greisenization). Although disseminated Sn mineralization may be associated with F and peripheral As, Pb and Zn anomalies in bedrock, these geochemical associations are not consistently developed. The intensely altered zones, however, which are characterized by topaz and abundant muscovite development, can be readily mapped mineralogically. Comparison of geochemical and mineralogical data suggested that the distribution of F reflects its occurrence in the alteration minerals (topaz and muscovite) and the primary igneous minerals (biotite and muscovite) and does not necessarily indicate alteration/mineralization. Therefore, mapping of mineralogical zonation can be important when direct observation of alteration is difficult, e.g. in areas of deep weathering and/or transported overburden.