Cinnabar

What it is

Cinnabar is mercury(II) sulfide (HgS), a mineral known for its vivid scarlet to brownish-red color and its heavy, almost waxy-diamond luster. It is soft (2 to 2.5 on the Mohs scale) and unusually dense, about eight times heavier than water, so even a small piece feels surprisingly weighty in the hand. It forms near volcanic activity and hot springs, and its main use has always been as the principal ore of mercury.

Where it comes from

Historic sources include Almadén in Spain, once the world's largest mercury mine, and Idrija in Slovenia. Both are now closed or greatly reduced. China remains an important source, particularly Guizhou and Hunan provinces, and cinnabar is also found in Peru and parts of the United States.

A long cultural history

Cinnabar has been prized for thousands of years, mostly for its color.

• Pigment: Ground cinnabar became vermilion, used in Roman frescoes, Chinese lacquerware, and imperial red seal ink.
• Chinese culture: Known as zhusha (朱砂), it appears in Daoist alchemy, talismans written in red, and traditional medicine texts, where it was associated with calming the spirit and warding off harm.
• Carved cinnabar lacquer: This craft, developed in China from the Song dynasty and flourishing in the Ming and Qing periods, builds up many layers of red lacquer that are then carved into landscapes and figures. Most of these pieces are lacquer tinted with cinnabar rather than solid stone.
• Feng shui and folk belief: Cinnabar is widely regarded as a protective, prosperity-attracting stone. It is often worn as bracelets or beads, or placed in homes and businesses.

Safety, which matters most

Because cinnabar is roughly 85% mercury by weight, it needs careful handling.

• Solid, intact pieces are generally considered low risk to touch or display, but wash your hands after handling.
• Avoid cutting, grinding, sanding, or heating it, which can release toxic dust or mercury vapor.
• Never ingest it. Traditional medicine uses are now strongly discouraged because of mercury poisoning risk.
• Keep it away from young children and pets, and avoid wearing it against the skin for long periods, particularly if the surface is worn or powdery.
• Prolonged exposure to light can dull or darken its color, so it is best stored away from direct sunlight.