Images (reflected light) of goethite present in different size fractions of iron ore tailings: (a) 150–105μm: botryoidal goethite (GoeB – centre) surrounded by quartz (Qz) and martitic hematite (HmM), (b) 592–420μm: crystal of botryoidal goethite (GoeB) evidencing its growth zoning, (c) 150–105μm: Mixt particle (centre) containing amphibolitic goethite (GoeAm) and quartz (Qz), (d) 6300–4760μm: alveolar goethite (GoeAl) with pores (Po) of various sizes and grains of kaolinite (Kao).