一種永久性的紅棕顏料，最早由天然紅赭土調製而成，但十八世紀開始，以煅燒硫酸亞鐵（綠礬）與石灰或碳酸鈣的方式製成，成分比例為約百分之十五到四十的氧化鐵和百分之六十至八十的硫酸鈣。用於油畫、房屋用漆，也可做為紙張著色劑。A permanent, reddish brown pigment that was originally prepared from a natural red ocher, but since the 18th century has been manufactured by calcining ferrous sulfate (copperas) with lime or calcium carbonate in a ratio of around 15-40% ferric oxide and 60-80% calcium sulfate. It is used in oil paints, house paints, and as a paper colorant.