The synthetic pigment Yellow Oxide is rapidly replacing the natural version. It has several advantages including more consistent quality and greater opacity. It is always much more pure than the natural product. It is suitable for use in all media and has been sold under a wide variety of names especially Mars Yellow and more recently Yellow Oxide. It is also manufactured in a very transparent grade called Transparent Yellow Oxide. Developed in the 19th century the Mars colors gained their names due to the similarities with the colors on the planet Mars at a time when controversial observations of canals on Mars were often in the news.