Iridescent Goethite From Spain GoethiteFormula: α-Fe3+O(OH)System: Orthorhombic.Hardness: 5 - 5½From: La Lapilla Mine, Alosno, Huelva, Andalusia, SpainDimensions: 12.1 cm x 8.4 cm x 3.8 cmCredit: © Fabre Minerals.