True Vermillion is a sulphide of mercury found in nature and also made by combining sulphur and quicksilver under suitable conditions. While a brilliant red, it is very expensive. Heat destroys it and exposure to atmospheric influences causes it to turn dark. All work painted with Vermillion should be varnished. The cheaper vermillions are mainly mixtures of red lead or orange mineral with eosine, a bright red aniline color, together with some base like barytes or terra alba. The amount of the latter substances used depending upon the price at which the vermillion must be sold. In some cases there is no lead present, being simply barytes, terra alba, or clay, tinted with eosine or red aniline dye. There are some special reds on the market, mixtures of various sorts, some containing iron oxides. None of these vermillions are absolutely permanent. The pinkish shades fade more quickly as depending on the aniline they contain for color, while those containing large percentages of lead or iron oxides are more permanent.