Zairite
Encyclopedia
Zairite is a phosphate mineral with the chemical formula Bi(Fe3+,Al)3[(OH)6|(PO4)2]. The name was given from where it was locally discovered in Eta-Etu, Kivu, Congo (Zaïre
) in 1975.
, which means it contains three equal horizontal axes with angles of 120° between them. The mineral has a trigonal-hexagonal scalenohedron shape. Zairite belongs to the uniaxial optical class. It means the light and vibrations passing through the mineral only has one direction it follows and it travels at the same speed.
(then Zaire) usually in the weathering areas of quartz
wolframite
deposits where it occurs with native bismuth
, bismutite, quartz and mica
. Zairite is found in granite
pegmatite
s, which are igneous coarse-grained rocks. It has also been reported from Kreuzberg Mountain in Upper Palatinate
, Bavaria
, Germany
.
Zaire
The Republic of Zaire was the name of the present Democratic Republic of the Congo between 27 October 1971 and 17 May 1997. The name of Zaire derives from the , itself an adaptation of the Kongo word nzere or nzadi, or "the river that swallows all rivers".-Self-proclaimed Father of the Nation:In...
) in 1975.
Properties
Zairite crystallizes in the trigonal crystal systemCrystal system
In crystallography, the terms crystal system, crystal family, and lattice system each refer to one of several classes of space groups, lattices, point groups, or crystals...
, which means it contains three equal horizontal axes with angles of 120° between them. The mineral has a trigonal-hexagonal scalenohedron shape. Zairite belongs to the uniaxial optical class. It means the light and vibrations passing through the mineral only has one direction it follows and it travels at the same speed.
Occurrence
The mineral was first described from the Eta-Etu district, northern Kivu Province, Democratic Republic of the CongoDemocratic Republic of the Congo
The Democratic Republic of the Congo is a state located in Central Africa. It is the second largest country in Africa by area and the eleventh largest in the world...
(then Zaire) usually in the weathering areas of quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
wolframite
Wolframite
Wolframite WO4, is an iron manganese tungstate mineral that is the intermediate between ferberite and huebernite . Along with scheelite, the wolframite series are the most important tungsten ore minerals. Wolframite is found in quartz veins and pegmatites associated with granitic intrusives...
deposits where it occurs with native bismuth
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...
, bismutite, quartz and mica
Mica
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition...
. Zairite is found in granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
pegmatite
Pegmatite
A pegmatite is a very crystalline, intrusive igneous rock composed of interlocking crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic....
s, which are igneous coarse-grained rocks. It has also been reported from Kreuzberg Mountain in Upper Palatinate
Upper Palatinate
The Upper Palatinate is one of the seven administrative regions of Bavaria, Germany, located in the east of Bavaria.- History :The region took its name first in the early 16th century, because it was by the Treaty of Pavia one of the main portions of the territory of the Wittelsbach Elector...
, Bavaria
Bavaria
Bavaria, formally the Free State of Bavaria is a state of Germany, located in the southeast of Germany. With an area of , it is the largest state by area, forming almost 20% of the total land area of Germany...
, Germany
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
.