Cinnabar

• 1. Introduction

  ›

  Cinnabar is the mineral that turned a Maya queen's tomb red. In the 7th century, a noble woman was laid in a sarcophagus at Palenque. Her remains, and every object that belonged to her, were completely covered in bright red powder. That powder was ground cinnabar, a scarlet to brick-red form of mercury(II) sulfide, and it gives the burial its modern nickname, the Red Queen. The same stone fed furnaces, decorated walls and carved boxes. It also killed people who handled it. Why did so many unconnected cultures reach for this one color? What happens when a rock is heated until it gives up a liquid metal? And what did it cost the workers who dug it out of the ground?

  37383524

• 2. A Name Of Many Meanings

  ›

  Cinnabarite and mercurblende are two other names for the same mineral. Both are older, narrower labels for a word that has always been slippery.

  The root is the Greek kinnabari. Theophrastus most likely used it for several different substances, so the ancient word never pointed to one mineral alone.

  Latin speakers sometimes called the material minium, a term that also meant red cinnamon. Today that Latin word refers specifically to lead tetroxide, a different red compound entirely.

  Whatever the ancients meant by their words, the mineral itself has measurable traits. Some of them are extreme.

  2653

• 3. Anatomy Of A Red Stone

  ›

  In its usual form, cinnabar appears as massive, granular or earthy lumps, colored from bright scarlet to brick-red. Occasionally it forms crystals with a nonmetallic adamantine luster. These are either thick and tabular or slender and prismatic, and they sometimes grow as simple contact twins. Its symmetry resembles that of quartz, and it is birefringent.

  A refractive index of 3.08 for sodium light makes cinnabar remarkable. Only one other mineral has a higher mean value. Diamond measures 2.42, while the non-mineral gallium arsenide measures 3.93.

  The stone is soft but heavy. It rates 2.0-2.5 on the Mohs scale, yet its specific gravity is 8.1.

  Inside the crystal, each mercury center sits close to two sulfur atoms, at 2.36 Å. Four more sulfur atoms hover farther off, at 3.10, 3.10, 3.30 and 3.30 Å.

  Mercury sulfide can also take a second shape, which makes it dimorphous. Metacinnabar is black and cubic, with the zincblende structure, and cinnabar is the more stable of the pair. A high-temperature form called hypercinnabar crystallizes in the hexagonal system.

  Hepatic cinnabar, or paragite, is an impure brownish variety from the Idrija mines in the Carniola region of Slovenia. There, the mineral is mixed with bituminous and earthy matter.

  Chemists can make the red form on demand. Mercury(II) salts treated with hydrogen sulfide give a black precipitate of synthetic metacinnabar. Heating that precipitate in water turns it red, and sodium sulfide speeds the conversion.

  410124042

• 4. Veins And Hot Springs

  ›

  At Sulphur Bank Mine in California and at Steamboat Springs in Nevada, cinnabar is still being deposited today. Watching those hot waters is the closest anyone can come to seeing the mineral form.

  Cinnabar usually fills veins in rock near volcanic activity and alkaline hot springs. Rising watery solutions lay it down close to the surface, at modest temperatures, far from the igneous source of the heat. It keeps company with native mercury, stibnite, realgar, pyrite, marcasite, opal, quartz, chalcedony, dolomite, calcite and barite.

  Almadén in Spain is the most famous locality. The mine was worked from Roman times until 2001, and for centuries it was the most important cinnabar deposit in the world. Good crystals have been found there.

  Nearly every place that yields mercury has cinnabar. In Egypt it occurs at Giza, and in the Philippines at Puerto Princesa. In the United States it is found at Red Devil in Alaska, Murfreesboro in Arkansas, and Terlingua in Texas. California adds the New Almaden Mine in San Jose, the Hastings and St. John's mines in Vallejo, and the New Idria area.

  In Europe, the list continues with Idrija in Slovenia and Avala in Serbia. Germany has Moschellandsberg near Obermoschel in the Palatinate. Tuscany has the La Ripa and Levigliani mines at the foot of the Apuan Alps, as well as Mount Amiata.

  Elsewhere, cinnabar comes from Huancavelica in Peru and the province of Guizhou in China. The Western Ghats of India have yielded fine crystals. In Dominica it appears near the sulfur springs at the southern end of the island, along the west coast.

  All of that rock was worth digging for what fire could take out of it.

  2021141518

• 5. Quicksilver And Its Cost

  ›

  Miners were already working cinnabar in the Neolithic Age. By the time of the Roman Empire, they dug it for two reasons: as a pigment, and for the mercury inside.

  Getting the metal out takes heat. Crushed ore goes into rotary furnaces and is roasted. Pure mercury separates from the sulfur and evaporates easily. A condensing column catches the vapor as liquid quicksilver, which is most often shipped in iron flasks.

  The Romans understood that this work harmed people. They treated mercury poisoning, called mercurialism, as an occupational disease.

  In ancient South America, people used cinnabar for art. They also processed it into refined mercury, which let them gild silver and gold objects. Even so, the toxic properties of mercury were well known there.

  The symptoms for miners and processors were shaking, loss of sense, and death. Data suggest that mercury was retorted from the ore, so workers breathed the toxic fumes.

  Almadén gave the grimmest verdict. One account reads: "Mining in the Spanish cinnabar mines of Almadén, 225 km southwest of Madrid, was regarded as being akin to a death sentence due to the shortened life expectancy of the miners, who were slaves or convicts."

  Modern precautions for handling the mineral descend from that ancient knowledge. The same concern still shapes how artisans work with its color.

  2845293830

• 6. A Color Across Cultures

  ›

  Five thousand years ago, at the dolmenic burial of La Velilla in Osorno, Palencia, in Spain, the dead were covered with care. A large amount of pulverized cinnabar lay over the bones.

  In the Near East, people had used the pigment since antiquity, including as a rouge-type cosmetic. In the New World, the tradition goes back to the Olmec culture.

  In China, the Yangshao culture used cinnabar to color stoneware. During the Zhou dynasty it served for writing on oracle bones.

  Roman builders prized it as paint, especially for interior walls. Outdoors, sunlight darkened it, which kept the best use indoors.

  In Chile, at Cerro Esmeralda in 1976, two female mummies were found. They have been dated to AD 1399-1475, and their clothes were colored with cinnabar.

  The mineral's appeal was not limited to graves and walls. In Almadén, it also found its way into gifts.

  3537382425

• 7. Carved Gifts And Lacquer

  ›

  Inside the Almadén mines, cinnabar sometimes appeared completely pure, as very dense microcrystalline masses. Powdered, it could color sealing wax with no purification at all. The material was also easy to carve, provided one overlooked the toxicity of mercury.

  The miners called it cinabrio de labra, meaning carving cinnabar. From the 18th century until the 1930s, some artisans in Almadén crafted objects from it to present to distinguished visitors.

  The best-known use of cinnabar is probably Chinese carved lacquerware, a technique that apparently began in the Song dynasty. Late in that dynasty, it was already being used to color lacquerware.

  Lacquer offers some protection. Entraining the powdered pigment in the lacquer may reduce the danger of mercury poisoning in ancient pieces. If such a piece is accidentally destroyed, however, it could still pose an environmental hazard.

  The modern jewellery industry avoids the question altogether. A resin-based polymer that approximates the look of pigmented lacquer replaces the toxic pigment.

  831321439