“…The optical properties of mineral dust varies dramatically between minerals, specifically, the absorption terms (k, the imaginary term) in their complex refractive indices, which can range from 1.5 (typical of quartz and calcite) up to about 3.2 (typical of hematite) (Sokolik and Toon, 1999). For instance, iron (Fe) rich minerals and clays absorb short wave (visible and ultraviolet) radiation, whereas quartz and calcium (Ca) rich minerals absorb more long wave (infrared) radiation (Sokolik and Toon, 1999;Hudson et al, 2008a;Hudson et al, 2008b;Kleiber et al, 2009;Klueser et al, 2012;Laskina et al, 2012). Individual particles in the atmosphere are often mixtures of multiple minerals (Ault et al, 2012;Sobanska et al, 2012;Jung et al, 2014;Sobanska et al, 2014), which complicates understanding their specific optical properties.…”