Cinnabar

• Mercury panel ( according to Breithaupt )
• Cinnabar

Cinnabar, known in German-speaking countries also known as cinnabar, is a commonly occurring mineral from the mineral class of " sulfides and sulfosalts ." It crystallizes in the trigonal crystal system with the composition of HgS, is so chemically seen a mercury sulfide.

Cinnabar is translucent to opaque and develops rarely larger, but usually very large area crystals with tabular to prismatic, rhombohedral or dipyramidalem habit. Hitherto been known about 50 crystal forms and crystal twins. Usually he can be found, however, in the form crusty coatings or grained to massive mineral aggregates. Visible crystal faces have a diamond-like luster, massive aggregates or crusts, however, are rather dull.

The color of Cinnabar is predominantly provided by a characteristic bright, easy- to yellow -leaning and also known as the color vermilion. Through foreign admixtures, mineral also assume a brownish-red to lead- gray color. However, his stroke color is always a strong red, which is described as scarlet.

With a Mohs hardness of 2 to 2.5 Cinnabar is one of the soft minerals that can be just similar to the reference mineral gypsum or halite even scratch with your fingernail. Cinnabar can be colored easily confused with realgar, with whom he appears frequently associated. However, it differs by its much higher density of this ( Cinnabar ≈ 8.2 g/cm3; realgar ≈ 3.6 g/cm3). More color similar minerals are cuprite, Krokoit, Proustite and rutile.

• 7.1 The raw material
• 7.2 The pigment

Special Features

Cinnabar has a conspicuously high birefringence ( δ = 0.351 ), which is about twice as high as that of this well-known calcite ( calcite, δ = 0.154 to 0.174 ). He also shows a very strong, the quartz to 15 times surpassing, circular polarization.

Before the blowpipe Cinnabarit sublimated very light (from 200 ° C) and heated with soda in the glow tube, is pure mercury settles out. Compared with acids and alkalis Cinnabar is however very stable, only in aqua regia and concentrated alkali sulfide solutions it dissolves.

Etymology and history

The name " Cinnabar " refers to the characteristic red color of the mineral and is derived from the Latin or the Greek Cinnabaris κιννάβαρι ( kinnabari ) and this in turn from Persian زینجیفرح ( " zinjifrah ": " Dragon's Blood " ) from. Under the name " dragon's blood " is also known as a red dye obtained from plants.

Cinnabar mines from the time of Baden culture are demonstrated, among other things Šuplja Stena in Serbia.

Historical application was Cinnabar as a red pigment, the " Vermilion ". The mercury contained was used after reduction of mercury sulfide as a material for mirror. As the mineral pigment has been used since ancient times in the Wall, Table and book illumination. The production of the two elements mercury and sulfur was probably invented in China in the Middle Ages (hence the common name " Chinesischrot "), while in Europe Cinnabar was first produced industrially from 1778.

Abraham Gottlob Werner (1749-1817) chose the name for the mineral cinnabar in its mineral systematics and ordered it as mercury ore in the class of metals. However, the final name of Cinnabar coined in 1859 Carl Friedrich Naumann ( 1798-1873 ), which refers to the original Latin form. Although H. Hugo A. Francke suggested in 1890 that the Greek spelling appropriate designation Kinnabarit, but just could not prevail; just as the chosen by August Breithaupt (1791-1873) Name Mercury aperture after the Roman god Mercury as a symbol of support for the mercury.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the Cinnabar belonged to the department of " sulfides with the molar ratio of metal: S, Se, Te ≈ 1: 1", where he along with Hypercinnabarit the unnamed group II / C .18 was formed.

The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the Cinnabar also in the department of "Metal Sulfides, M: S = 1: 1 ( and similar ) " a. However, this is further subdivided according to the conditions prevailing in the interconnect metals, so that the mineral according to its composition in the subdivision " with tin ( Sn ), lead ( Pb ), mercury (Hg ), etc. " is to find where it is the only Member forms the unnamed group 2.CD.15a.

The mainly common in English-speaking classification of minerals according to Dana assigns the Cinnabar in the class of " sulfides and sulfosalts " and there in the department of " sulfide minerals ." Here he is the only member of the unnamed group 02:08:14 within the subdivision " sulfides - with the composition AmBnXp, with (m n) - including selenides and tellurides: p = 1:1 " to find.

Modifications and varieties

Cinnabar is one of three modifications of mercury sulfide ( HgS ). The other two are the cubic crystalline Metacinnabarit and the hexagonally crystallized Hypercinnabarit.

As Stahlerz a bluish variety is called with metallic luster.

Education and Locations

Cinnabar hydrothermally formed mainly in fracture zones around volcanic vents and hot springs. Accompanying minerals include stibnite, arsenopyrite, calcite, chalcedony, dolomite, fluorite, marcasite, pyrite, quartz, mercury and realgar.

As a frequent mineral formation Cinnabar is found in many localities, where so far (as of 2013) over 2300 localities are known. One of the most important deposits but include the Monte Amiata in Italy, Idrija in Slovenia, Almaden in Spain, Nikitovka ( Donetsk Oblast ) in Ukraine and Fargona in Uzbekistan.

Known due to exceptional Cinnabaritfunde is especially China, where, Guizhou and other provinces well-developed crystals of up to seven centimeters in size were revealed at numerous sites in Hunan.

In Germany, the mineral found in many places in the Black Forest in Baden- Württemberg, in Wölsendorf in the Bavarian district Schwandorf, in several places in Hesse and Lower Saxony, in the Sauerland and winners district of North Rhine -Westphalia, in many places in Rhineland -Palatinate and in some places in Saarland, Saxony- Anhalt, Saxony and Thuringia.

In Austria Cinnabarit previously appeared primarily in Carinthia, Salzburg, Styria and Tyrol.

In Switzerland, the mineral previously could only be found in two places in Shams in the canton of Graubünden and in several places in the canton of Valais.

Other localities lie include Afghanistan, Australia, Bolivia, Chile, France, Japan, Canada, Kyrgyzstan, Mexico, Russia, Zimbabwe, Slovakia, Czech Republic, Hungary, the United Kingdom ( UK) and in many states of the USA.

Synthetic production

Vermilion can chemically composed of mercury (II) salt solutions are precipitated sulphide by passing hydrogen sulfide as mercury (II). Initially falls from the metastable, black, cubic sulfide ( Metacinnabarit ). This comes in contact with ammonium polysulphide in the course of a few days in the less soluble, red hexagonal modification over.

Crystal structure

Cinnabar crystallizes in the trigonal crystal system in the space group P3121 ( Raumgruppen-Nr. 152) or P3221 ( Raumgruppen-Nr. 154) with the lattice parameters a = 4.15 Å and c = 3.26 Å and three formula units per unit cell.

Use

The raw material

Cinnabar is the most important and most common mineral mercury with a metal content of 87 percent.

The pigment

As a red color pigment, it is extremely hard water and can thus be safely used in artists' paints or color box as vermilion. Cinnabar has a good coverage, but can be dyed dark in strong light. As a painter, color can cinnabar also found under the following names:

Vermilion, Cinnabar, Mercurblende, Minium, Quecksilbersulfidrot, Red sulphide of mercury, Chinesischrot and Vermillion.