VERMILION  , a

scarlet pigment composed of mercuric sulphide, HgS . It may be obtained direct from pure and bright coloured portions of the native ore cinnabar, or, artificially, by subliming a mixture of mercury and sulphur . The product is ground and levigated; and when dry it is ready for use . It is also prepared by digesting precipitated mercuric sulphide with an alkaline sulphide for some hours; it is said that Chinese vermilion owes its superiority to being made in this way . In addition to its brilliance, vermilion is a pigment of great intensity and durability, remaining unaffected by acid fumes . Being costly, it is much subject to adulteration; but the fraudulent additions may easily be detected by volatilization, which in the case of pure vermilion leaves no residue . See FIGMENTS and MERCURY .