Hematite, Jarosite, Quartz

From: Filon 340, Rodalquilar, Níjar, Almería, Andalusia, Spain

Iridescent hematite, also called rainbow hematite, displays a variety of beautiful interference colours. Usually, a thin film comprised of aluminium and phosphate was found to coat such hematite, although one example of a coating with aluminium and arsenate was discovered. The thin films that range from tens to hundreds of nanometers thick are believed to cause the colour.

Jose Miguel Sola Fdez.’s Photo