Today, vermilion is most commonly artificially produced by reacting mercury with molten sulfur. Most naturally produced vermilion comes from cinnabar mined in China, giving rise to its alternative name of China red.
The synthetically-produced pigment was used throughout Europe from the 12th century, mostly for illuminated manuscripts, although it remained prohibitively expensive, often costing as much as gilding, until the 14th century when the technique for synthesizing vermilion became more widely known in Europe. Synthetic vermilion was regarded early on as superior to the pigment derived from natural cinnabar. Cennino Cennini mentions that vermilion is
...made by alchemy, prepared in a retort. I am leaving out the system for this, because it would be too tedious to set forth in my discussion all the methods and receipts. Because, if you want to take the trouble, you will find plenty of receipts for it, and especially by asking of the friars. But I advise you rather to get some of that which you find at the druggists' for your money, so as not to lose time in the many variations of procedure. And I will teach you how to buy it, and to recognize the good vermilion. Always buy vermilion unbroken, and not pounded or ground. The reason? Because it is generally adulterated, either with red lead or with pounded brick.
In the Dutch method of manufacturing vermilion used from the 17th century, which was a modified version of the Chinese method, mercury and melted sulfur were mashed together to make black mercury sulfide, which was heated in a retort. This caused it to give off vapor which condensed as the bright red crystalline form of mercury sulphide, which was then scraped off and treated with a strong alkali solution to remove sulfur, then washed and ground under water.
The names "cinnabar" and "vermilion" were used interchangeably to describe either the natural or manufactured pigment until the 17th century when vermilion became the more common name. By the late 18th century the name cinnabar was applied only to the unground natural mineral.
"Chinese vermilion" was described in 1835 as a cinnabar so pure that it only had to be ground into powder to become a perfect vermilion. Chinese vermilion was considered of a more crimson tone than the vermilion manufactured in Europe from less pure cinnabar. European vermilion of the time was often cut with various materials due to its high cost; adulterants included brick dust, orpiment, iron oxide, Persian red, iodine scarlet, and red lead, an inexpensive bright lead oxide pigment that was too reactive to be trustworthy enough for use in art.
Vermilion is also the name of the typical color of the natural ground pigment, which is a bright red tinged with orange. It is somewhat similar to the color scarlet. Vermilion is not on the color wheel since the color is mixed with a slight amount of grey. As with cadmium sulfide, mercuric sulfide can be found in a range from a bright orange-toned red to a duller slightly bluish red. The differences in hue are due to the range in the size of the ground particles. The larger the average crystal is, the duller and less orange-toned it appears. It has been theorized that the more coarsely ground "Chinese" form of vermilion is more permanent than the more orange "French" variety. It is also theorized that purification leads to increased stability, as with many other pigments.
Hindu women use vermilion along the hair parting line known as Sindoor, to signify that they are married. Hindu men often wear the vermilion on their forehead during religious ceremonies. Vermilion is part of all religious ceremonies and festivals.
Displayed at right is the web color orange-red, which has a special significance in hacker culture. The documentation for Digital Equipment Corporation's VMS version 4 came in memorable, distinctively-colored orangish-red ring binders, and "China red" was Digital's official name for this color. (According to http://www.inwap.com/pdp10/usenet/history.9612, Mark Crispin seems to claim Digital's name for the color was Terracotta, at least in the context of PDP-10 machines running Tops-20.)