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.