Columbite

Columbite ( Columbeisen, Niobit ) is not an independent mineral, but a collective term for an unspecified mixed crystal of the series columbite - (Fe), columbite - (Mg) and columbite - (Mn). The mixed crystals crystallize as the Endminerale this series in the orthorhombic crystal system. These show the following color and chemistry:

• Columbite - (Fe) (formerly Ferrocolumbit ): brownish -gray-white; Fe2 Nb2O6
• Columbite - (Mg) (formerly Magnocolumbit or Magnesiocolumbit ): brownish - black; MgNb2O6
• Columbite - (Mn ) (formerly Manganocolumbit ): brownish - black to black; Mn2 Nb2O6

The columbite - series also forms a mineral series with the mineral tantalite and is registered with the International Mineralogical Association (IMA ) as a group name. The mixed crystals ( and ores) in this series are known as coltan.

Etymology and history

The first record was in the middle of the 17th century in Colombia, from which the name derives. Only in 1844 was able to demonstrate the German chemist Heinrich Rose, columbite that contains two elements, namely niobium and tantalum.

Education and Locations

Columbite are usually found in granite rocks ( pegmatites ), among others

• At ground corn (ie pegmatite chicken Kobel ), Hagendorf (Bavaria) and Tirschenreuth in East Bavaria,
• At Chanteloup ( Razès ) in France,
• In Finland, Norway (eg Evje and Iveland in Aust -Agder ), Sweden (eg Varuträsk )
• In Ilmengebirge at Mijask,
• In Madagascar
• In Connecticut, Massachusetts, North Carolina and Colorado in the United States and
• In Greenland Ivigtut in a cryolite - pegmatite.

Use

Columbite is an important ore for the extraction of niobium ( named because niobium has been called up to the 1950s columbium) and tantalum, which are added to increase strength steel alloys.