There is a variety of corrosion surfaces and corrosion interfaces on glass associated with the development of patina. This has been determined by examination of patina/glass contacts in ‘mature’, older patina, some 100 years old and 20 years old, in Australian settings, and in experimentally-produced patina in the laboratory. The form of these corrosion surfaces and corrosion interfaces largely determines, in the next stage of patina accretion, the form of accretionary patina as it invades glass. The types of corrosion surfaces and corrosion interfaces recognized are: large irregular, shallow concave depressional, scalloped or cuspate, lobate/semi-lobate solutional invasion fronts, meso-etched, micro-etched, plain, fungal micro-bore architecture (invaginated), cuspate structure, and brecciated. The various types of corrosion surfaces and corrosion interfaces appear to reflect the heterogeneity of glass chemistry and extent of fungal bio mediation. The geometry of the corrosion surfaces determines the geometry of accretionary patina.