rubefaction
/ˌruːbɪˈfakʃn/(also rubifaction)
noun
1 Medicine. Reddening or redness of the skin, especially as produced by a rubefacient; the action of using a rubefacient; an instance of this. Now rare.
2 Geology and Soil Science. Reddening of rock or soil due to the deposition and oxidation of iron compounds during prolonged weathering; the process by which such reddening is produced.
Origin
Late Middle English; earliest use found in Guy de Chauliac's Grande Chirurgie. From rubify: see -faction.