Mars YellowColor: Mars YellowPermanence: AAOpacity: OpaquePigment: PY42Pigment description: Synthetic Iron OxideASTM Rating Ligthfastness: IPigment classification: Synthetic inorganicColor Index Number: 77492Viscosity range (mPa. s): 800 1. 500 Color IndexThe pigments used for artists colors are inorganic as well as organic. The inorganic pigments have been used since antiquity; most of them are extracted from minerals and soil, such as natural earth colors,