FTIR – main clay peak (Si–O): 1079.9 cm⁻¹ (1077–1081 cm⁻¹ quartz-overlap window; high firing supported by band width ~188 cm⁻¹ and loss of clay OH); calcite: Trace only (ν₃ 1429.0 cm⁻¹ weak; ν₂ 875 not detected — largely decomposed); quartz: 796.5 cm⁻¹, 778.1 cm⁻¹; dolomite: Uncertain (weak 729.4 cm⁻¹, inconsistent with band position — verify petrographically) (refs: B07; R10)
