Bornite

• Deep - bornite
• Bornite

Bornite (deep - bornite ), also called bornite, Kupferlasurerz or copper Lazur, is a commonly occurring mineral from the mineral class of " sulfides and sulfosalts ". It crystallizes in the orthorhombic crystal system with the chemical composition Cu5FeS4 and usually develops massive aggregates, crystals rare in octahedron or pseudocubic form in bronze or copper color.

Special Features

Before the blowpipe melts bornite to a gray and magnetic ball. In nitric acid and concentrated hydrochloric acid dissolves the mineral, sulfur being deposited.

In the fresh state with bornite and pyrrhotite Nickeline may be mistaken, bluish- green or variegated color started also the chalcopyrite or covellite.

Etymology and history

Bornite had been known since 1725, it got its official name, but only in 1845 by Wilhelm Ritter von Haidinger, who named the mineral after the Austrian mineralogist Ignaz von Born. His mining designation bornite received the mineral because it forms in air very quickly colorful tarnish.

As a type locality applies Jáchymov ( German Jáchymov ) in the Czech Republic.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the bornite belonged to the mineral class of " sulfides and sulfosalts " and then to the Department of " sulfides with the molar ratio of metal: sulfur, selenium, tellurium > 1: 1 " where he along with Betechtinit, Gortdrumit and Calvertit the group of " complexes copper-iron sulfides" with the system no. II/B.02 formed.

The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the bornite also in the class of " sulfides and sulfosalts " and there in the department of "Metal Sulfides, M: S> 1: 1 ( mainly 2: 1) " a. This division, however, is further subdivided according to the conditions prevailing in the interconnect metals, so that the mineral according to its composition in the subdivision " with copper ( Cu), silver (Ag ) and / or gold ( Au) " can be found, where it acts as single member of the unnamed group forms 2.BA.10.

The mainly common in English-speaking classification of minerals according to Dana assigns the bornite in the class of " sulfides and sulfosalts " and then in the Department of " sulfide minerals ." Here he is the only member of the unnamed group 02:05:02 within the sub-division of " sulfides - with the composition AmBnXp, with (m n) - including selenides and tellurides: p = 3:2 " to find.

Education and Locations

Bornite can arise in different ways. Most, however, it forms primarily as well as secondarily of chalcopyrite with magnetite, hematite or chalcocite in low-iron copper deposits. Pneumatolytic by and hydrothermal processes within pegmatites or skarns Examples of this development forms include Butte ( Montana), Tsumeb (Namibia), Musina (formerly Messina, South Africa), Tamaya ( Región de Coquimbo, Chile ) and the winning country and Berggießhübel ( Germany ).

Rarely, bornite also occur magmatic or sedimentary such as in the Mansfeld copper shale and very rarely as a deposit in the cementation of mineral deposits or in alpine ravines.

Bornite weathered relatively easily through the intermediate stages chalcocite, covellite and malachite and azurite to Idait. Accordingly, in paragenesis with the minerals mentioned so far, it appears, but also other copper and iron minerals such as And pyrite with calcite, various shells, quartz and wollastonite.

Overall, bornite so far (as of 2011) are detected around 4,200 localities. Apart from its type locality Jáchymov ( Jáchymov ) the mineral still occurred in the Czech Republic in many other places of Bohemia and Moravia, so among other things Příbrami, the Hradec Králové Region and Karlovy Vary (Carlsbad), Silesia and the highlands.

Noteworthy due to exceptional Bornitfunde among other Bisbee in the U.S. state of Arizona, where on the one hand and on the other hand extremely heavy masses of crystals up to 2 cm in diameter ( " Cole Mine" ) were brought to light. Beautifully developed crystals of up to 4 cm in size was found in the " Dzhezkazgan Mine" in the area of ​​Karaganda in Kazakhstan. From Likasi in the Congolese province of Katanga crystal skin - Fund are known from about 3 cm in size and from Carn Brea in Cornwall (England ) are usually about 1 cm large crystals.

Other localities lie in Afghanistan, Egypt, Angola, Antarctica, Argentina, Armenia, Australia, Azerbaijan, Belgium, Bolivia, Botswana, Brazil, Bulgaria, Chile, China, Costa Rica, Germany, Dominican Republic, Ecuador, Eritrea, on Fiji, Finland, France, Ghana, Greece, Greenland, Haiti, Honduras, India, Indonesia, Iran, Ireland, Italy, Jamaica, Japan, Canada, on the Channel Island of jersey, in Kyrgyzstan, the Democratic Republic of Congo, Colombia, North and South Korea, Kosovo, Cuba, Madagascar, Malaysia, Mali, Morocco, Macedonia, Mexico, Mongolia, Myanmar, Namibia, New Zealand, Norway, Oman, Austria, Pakistan, Panama, Papua New Guinea, Peru, the Philippines, Poland, Portugal, Puerto Rico, Romania, Russia, on the Solomon Islands, Zambia, Saudi Arabia, Sweden, Switzerland, Serbia, Sierra Leone, Zimbabwe, Slovakia, Slovenia, Spain, South Africa, Swaziland, Taiwan, Thailand, the Turkey, Hungary, Venezuela, the United Kingdom ( UK), the United States of America ( USA) and Cyprus.

Also in several rock samples from the Mid-Atlantic Ridge, the Central Indian ridge and the East Pacific Rise and outside the earth on the moon bornite could be detected.

Crystal structure

Bornite crystallized first as a high - bornite ( β - Cu5FeS4 ) in the cubic crystal system in the space group Fm3m ( Raumgruppen-Nr. 225 ) with the lattice parameters a = 5.50 Å, and one formula unit per unit cell. After further cooling it changes at about 270 to 265 ° C in intermediate bornite with metastable cubic structure to eventually move at about 205 to 195 ° C in the stable, orthorhombic low - bornite, whose unit cell lattice parameters a = 10.95 Å; b = 21.86 Å and c = 10.95 Å, and has the 16 formula units in the space group Pbca ( Raumgruppen-Nr. 61) are arranged.

Use

Bornite is an important copper ore due to its high copper content of about 63 weight percent, and its widespread occurrence.