Cinnabar is a bright red mineral made mostly of mercury and sulfur. Its chemical formula is HgS, or mercury sulfide.
People have valued cinnabar for its vivid scarlet color. Historically, it was ground into a red pigment called vermilion, used in art and decoration. Cinnabar is also the main natural ore from which mercury can be obtained.
Why handle it carefully?
Cinnabar contains mercury. Although the mercury is bound in the mineral, cinnabar dust and fumes—especially if it is heated or processed—can be hazardous. It should not be ground, heated, or handled casually.
In short, cinnabar is a striking red mercury-bearing mineral with an important history, but it requires care because of its mercury content.