Pentlandite

Pentlandite, outdated also known as iron-nickel gravel, Folgerit or Lillehammerit, is a commonly occurring mineral from the mineral class of " sulfides and sulfosalts ." It crystallizes in the cubic crystal system with the chemical composition of (Ni, Fe) 9S8 and developed largely opaque to massive granular mineral aggregates rarely but also crystals to about 10 m in size of a light bronze color to red-brown.

Pentlandite forms with Cobaltpentlandit a perfect mixed batch.

Special Features

Pentlandite, in contrast to pyrrhotite paramagnetic and will not react with hydrochloric acid.

Etymology and history

Pentlandite was named after its discoverer Joseph Barclay Pentland (1797-1873), an Irish naturalist and geographer. The alternative name ferronickel gravel derived from the high iron and nickel content of the mineral.

Was first discovered in 1856 in the pentlandite " Craignure Mine" at Inveraray in Scotland's Strathclyde region or at Espedalen in Norwegian Sør- Fron and described by Armand Dufrenoy.

Classification

In the old ( 8th edition ) and new classification of minerals according to Strunz ( 9th edition ) of pentlandite is part of the Department of " sulfides and sulfosalts with the molar ratio of metal: sulfur ( selenium, tellurium )> 1: 1", the department in the 9th edition adding " mainly 2: 1" carries. In addition, the department in the 9th edition is divided according to the precise nature of the cations involved and the pentlandite is in accordance with the subdivision " with nickel ( Ni) ," where he along with Argentopentlandit, Cobaltpentlandit, Geffroyit, Manganshadlunit and Shadlunit the unnamed group 2 forms. BB.15a.

The commonly used in English-speaking classification of minerals according to Dana assigns the pentlandite also in the class of sulfides, there, however, in the department " sulfides - including selenides and tellurides - with the composition AmBnXp, with (m n): p = 9: 8 ". There he is as Leitmineral the Pentlanditgruppe ( isometric: Fm3m ) with the other members Argentopentlandit, Cobaltpentlandit, Shadlunit, Manganshadlunit and Geffroyit.

Education and Locations

Pentlandite is usually liquid magmatic in ultramafic rocks. The most important partner is the paragenesis of pyrrhotite, with which it occurs often intimately connected. This is due to the disintegration of the solid solution phase of pentlandite and pyrrhotite on cooling below 610 ° C, forming characteristic flame-shaped Entmischungskörper of pentlandite in pyrrhotite or located on the grain boundaries of pyrrhotite. This Verwachsungsaggregat is also known under the name nickel pyrrhotite. Other accompanying minerals are chalcopyrite, cubanite, mackinawite, magnetite and troilite.

Was Worldwide pentlandite so far (as of 2010) detected at around 820 localities, so include Afghanistan, Albania, Argentina, Australia, Ethiopia, Bolivia, Botswana, Brazil, Bulgaria, Burkina Faso, China, Germany, Finland, France, Ghana, Greece, Greenland, India, Indonesia, Italy, Jamaica, Japan, Yemen, Canada, Kazakhstan, Democratic Republic of the Congo, North and South Korea, Cuba, Madagascar, Mexico, Morocco, Namibia, New Caledonia, New Zealand, Norway, Oman, Austria, Pakistan, Philippines, Poland, Portugal, Romania, Russia, Sweden, Switzerland, Sierra Leone, Zimbabwe, Slovakia, Spain, South Africa, Trinidad and Tobago, Turkey, Uganda, Ukraine, the United Kingdom ( UK), in the United States ( U.S.) and in Vietnam.

Even in rock samples of the Mid-Atlantic Ridge and in the Mare Crisium on the Moon and in the comet dust from Wild 2 pentlandite could be detected.

The most important deposit is located in Greater Sudbury ( Canada). Other occurrences of pentlandite can be found in Quebec City (Canada), California, Norway, South Africa and Russia.

Crystal structure

Pentlandite crystallized in cubic space group Fm3m ( Raumgruppen-Nr. 225 ) with the lattice parameters a = 10.04 Å and four formula units per unit cell.

In the structure of spinel are here the sulfur ions in cubic closest packing ago. Of the metal ions are octahedrally each 4 to 32 per tetrahedral coordination with sulfur.

Use

In addition to the garnierite also includes the pentlandite with a nickel content of 34 % to the most important nickel ores.