Treatise on Poisons by Sir Robert Christison

Cinnabar or vermilion, the bisulphuret of mercury, usually exists in the arts in the form of a fine, heavy, red powder, of a peculiar tint, which is termed from this substance vermilion-red. In mass its structure is coarsely-fibrous, and its colour reddish-brown; and it has some lustre. When thrown down from a solution of corrosive sublimate by sulphuretted-hydrogen, or the alkaline hydrosulphates, it forms a black powder, which acquires a red tint by being sublimed. It is composed of 101 metal and 16 sulphur. It is distinguished from other substances by the operation of heat, and by the effects of reduction with iron filings. Heated alone in a tube it sublimes without change. Its colour, indeed, which is fugacious under heat unless particular manipulations are used, becomes darker and dingy; but its lustre and crystalline texture are retained. Heated with iron filings in a tube, it gives off globules of mercury; and the existence of sulphuret of iron in what remains may be proved by the escape of sulphuretted-hydrogen on the addition of diluted sulphuric acid.