Bournonite

• Rädelerz

Bournonite ( Rädelerz, Spießglanzbleierz, Schwarzspießglanzerz, Wölchit ) is a commonly occurring mineral from the mineral class of sulfides and sulfosalts. It crystallizes in the orthorhombic crystal system with the chemical composition PbCu [ SbS3 ] and develops a short, or prismatic, tabular crystals, but granular or massive aggregates of steel-gray to black in color for the same color bar. On the surfaces of opaque crystals is reflected in fresh samples of strong metallic luster, older samples, however, run occasionally bluish and become dull.

Special Features

Bournonite contains about 42 % lead, 13% copper, 25 % antimony and 20 % sulfur. Before the blowpipe, it can easily melt into a black sphere with antimony smoke.

In nitric acid dissolves Bournonite with separation of sulfur and antimony on

Etymology and history

The initially identified by Philip Rashleigh 1797 Endellionit mineral was renamed after the determination by Bournon 1804 by Robert Jameson in Bournonite. Jacques Louis de Bournon (1751-1825) was a French crystallographer and mineralogist. The mining Rädelerz name was created by the frequent finding of Vierlingsverwachsungen the Bournonite crystals that look like a gear.

Was first discovered in the Bournonite " Wheal Boys Mine" (also Trewetha mine ) at St. Endellion in the English county of Cornwall.

Classification

In the classification by Strunz Bournonite is classified in the sulfides and sulfosalts. In the 8th edition he made with Seligmannit a group of sulfosalts. In the 9th edition of the sulfides are further subdivided according to cations, there is Stromeyerite together with Seligmannit and Soucekit in a group of island - Sulfarsenide without additional sulfur.

In the scheme of minerals by Dana Bournonite forms with Seligmannit and Soucekit a subset of sulfosalts with the composition ( A ) i ( A2 ) j [By Cz ] and a ratio of z to y > 3 (A: Metals, B: semi-metals C: non-metals ).

Education and Locations

Bournonite formed hydrothermally in moderate zinc, lead and copper ore. Accessory minerals are galena, tetrahedrite, pyrite, siderite and others.

Worldwide, Bournonite so far (as of 2011) are detected at around 850 localities. Apart from its type locality " Wheal Boys Mine" the mineral in the United Kingdom (Great Britain) still occurred in several places of the English counties of Cornwall and Cumbria and in Wales and Scotland revealed.

Known sites because of unusual Bournonitfunde include Machacamarca in the Bolivian Potosí Departemento and Saint- Laurent- le- Minier in the French department of Gard, where crystals were up to 10 cm in size have been found. In the " Herodsfoot Mine" at Lanreath in Cornwall complex Rädelerz twins were supported by more than 5 cm in size and up to 4 cm large crystals were found in Pribram in the Czech Republic and in the Huancavelica region of Peru.

In Germany Bournonite was in several places of the Black Forest in Baden- Württemberg, in Franconia and the Upper Palatinate in Bavaria, at Laubuseschbach in central Hesse, at Clausthal and Saint Andreas mountain in Lower Saxony Harz, at several findspots the Eifel and the winner's country of North Rhine -Westphalia and Rhineland -Palatinate, in the Sauerland, Bergisch Land in North Rhine-Westphalia, in the Saarland Nonnweiler community, at Neudorf and Wolfsberg in Saxony- Anhalt, at Freiberg and Schneeberg in Saxony's Erzgebirge and in Gera, Greiz and Saalfeld in Thuringia.

In Austria, can the mineral in several regions of Carinthia, Salzburg and Styria, and find the Eichberg at Gloggnitz in Lower Austria and the Inn and Silltal in Tirol and Switzerland were found there in the Ticino region Malcantone as well as in the Binn Valley and the community Collonges VS in the canton of Valais.

Other localities are Argentina, Ethiopia, Australia, Bolivia, Brazil, Bulgaria, Chile, China, Fiji, Finland, Ghana, Greece, Greenland, Indonesia, Ireland, Italy, Japan, Jersey, Channel Islands, Canada, Kazakhstan, Kyrgyzstan, Colombia, Korea, Croatia, Kosovo, Mexico, Mongolia, Namibia, New Zealand, Peru, Poland, Portugal, Romania, Russia, Sweden, Slovakia, Slovenia, Spain, South Africa, Tajikistan, Tunisia, Ukraine, Uzbekistan, the United States of America (USA ) and Vietnam.

Crystal structure

Bournonite crystallizes in the orthorhombic crystal system, space group Pn21m ( Raumgruppen-Nr. 31) with the lattice parameters a = 8.15 Å, b = 8.69 Å and c = 7.79 Å and four formula units per unit cell.

Use

Bournonite is an important lead and copper ores and is used as a raw material for the extraction of these elements.