1911 Encyclopædia Britannica/Vermilion

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 levitated; 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 Pigments and Mercury.