The synthetic iron oxide colors introduced in the mid 19th century have gradually (under various names) supplanted most of the natural Earth Colors. They are equally permanent but are more pure in color and importantly, consistent in quality. These days colors like Indian Red, Venetian Red, Yellow Oxide, Mars Black or Iron Black, Transparent Red Oxide, Transparent Yellow Oxide, Pozzuoli Red, Caput Mortuum, and Mars Violet are all made with Mars colors, and every one of them strong and useful in their own way.