Baotite
Encyclopedia
Baotite Ba
4Ti
4(Ti
, Nb
, Fe
)4(Si
4O
12)O16Cl
is a rare mineral recognized as having a unique four-fold silicate ring. Crystals are tetragonal, though commonly deformed to the extent of appearing monoclinic. Named for the locality of first discovery, Baotou
, China, baotite has been found in hydrothermal veins and alkalic rocks in various locations around the world.
share edges, forming chains and cross-linking at the corners forming a 4-fold screw axis
in the (001); these columns are analogous to those in rutile
. Four silicate
tetrahedra share corners creating characteristic rings in the plane perpendicular to the c axis. The barium cation is between the rings and rutile columns, while chloride fills the void between each pair of rings. Chlorine’s presence is not necessary for the structure to balance electrostatically.
, pyrite
, albite
, aegirine
and alkali amphibole
s in a quartz
vein cutting quartzite
at the Bayan Obo
Mine in China. Grains from Ravalli County, Montana
were found in a thin calcite
crust on masses of eschynite within a carbonatic
vein. Baotite also occurs at Haast River
, New Zealand as an accessory phase of carbonatite
, fenite and hydrothermal fluid veins associated with a dike swarm
. The dike
intrusion of mantle-derived magmas can likely be attributed to the close proximity of the Alpine fault
plate boundary across South Island, New Zealand.
Barium
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in Group 2, a soft silvery metallic alkaline earth metal. Barium is never found in nature in its pure form due to its reactivity with air. Its oxide is historically known as baryta but it reacts with...
4Ti
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
4(Ti
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
, Nb
Niobium
Niobium or columbium , is a chemical element with the symbol Nb and atomic number 41. It's a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite...
, Fe
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
)4(Si
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
4O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
12)O16Cl
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
is a rare mineral recognized as having a unique four-fold silicate ring. Crystals are tetragonal, though commonly deformed to the extent of appearing monoclinic. Named for the locality of first discovery, Baotou
Baotou
Baotou is a mid-sized industrial city in the Inner Mongolia Autonomous Region of the People's Republic of China. Governed as a prefecture-level city, its urban areas are home to a population of approximately 1.78 million, with a total population of over 2.65 million accounting for counties under...
, China, baotite has been found in hydrothermal veins and alkalic rocks in various locations around the world.
Structure
Simonov first determined the crystal structure of baotite in which (Ti, Nb, Fe)-octahedraOctahedron
In geometry, an octahedron is a polyhedron with eight faces. A regular octahedron is a Platonic solid composed of eight equilateral triangles, four of which meet at each vertex....
share edges, forming chains and cross-linking at the corners forming a 4-fold screw axis
Screw axis
The screw axis of an object is a line that is simultaneously the axis of rotation and the line along which a translation occurs...
in the (001); these columns are analogous to those in rutile
Rutile
Rutile is a mineral composed primarily of titanium dioxide, TiO2.Rutile is the most common natural form of TiO2. Two rarer polymorphs of TiO2 are known:...
. Four silicate
Silicate
A silicate is a compound containing a silicon bearing anion. The great majority of silicates are oxides, but hexafluorosilicate and other anions are also included. This article focuses mainly on the Si-O anions. Silicates comprise the majority of the earth's crust, as well as the other...
tetrahedra share corners creating characteristic rings in the plane perpendicular to the c axis. The barium cation is between the rings and rutile columns, while chloride fills the void between each pair of rings. Chlorine’s presence is not necessary for the structure to balance electrostatically.
Geologic occurrence
The first sample of baotite was found with galenaGalena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...
, pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...
, albite
Albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. As such it represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula NaAlSi3O8. It is a tectosilicate. Its color is usually pure white, hence...
, aegirine
Aegirine
Aegirine is a member of the clinopyroxene group of inosilicates. Aegirine is the sodium endmember of the aegirine-augite series. Aegirine has the chemical formula NaFeSi2O6 in which the iron is present as Fe3+. In the aegirine-augite series the sodium is variably replaced by calcium with iron and...
and alkali amphibole
Amphibole
Amphibole is the name of an important group of generally dark-colored rock-forming inosilicate minerals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures.-Mineralogy:...
s in a 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,...
vein cutting quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
at the Bayan Obo
Bayan Obo
Bayan Obo Mining District, , or Baiyun-Obo or Baiyun'ebo, is a mining town in the west of Inner Mongolia, People's Republic of China. It is under the administration of Baotou City, more than to the south....
Mine in China. Grains from Ravalli County, Montana
Ravalli County, Montana
-National protected areas:*Bitterroot National Forest *Lee Metcalf National Wildlife Refuge*Lolo National Forest -Demographics:As of the census of 2000 , there were 36,070 people, 14,289 households, and 10,188 families residing in the county. The population density was 15 people per square mile...
were found in a thin calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
crust on masses of eschynite within a carbonatic
Carbonate minerals
Carbonate minerals are those minerals containing the carbonate ion: CO32-.-Anhydrous carbonates:*Calcite group: Trigonal**Calcite CaCO3**Gaspeite CO3**Magnesite MgCO3**Otavite CdCO3**Rhodochrosite MnCO3**Siderite FeCO3**Smithsonite ZnCO3...
vein. Baotite also occurs at Haast River
Haast River
The Haast River has its terminus on the West Coast of the South Island of New Zealand.The Haast River drains the western watershed of the Haast Pass. It is 100 kilometres in length, and enters the Tasman Sea near Haast township. The river's main tributary is the Landsborough River.The grassy flats...
, New Zealand as an accessory phase of carbonatite
Carbonatite
Carbonatites are intrusive or extrusive igneous rocks defined by mineralogic composition consisting of greater than 50 percent carbonate minerals. Carbonatites may be confused with marble, and may require geochemical verification....
, fenite and hydrothermal fluid veins associated with a dike swarm
Dike swarm
A dike swarm or dyke swarm is a large geological structure consisting of a major group of parallel, linear, or radially oriented dikes intruded within continental crust. They consist of several to hundreds of dikes emplaced more or less contemporaneously during a single intrusive event and are...
. The dike
Dike (geology)
A dike or dyke in geology is a type of sheet intrusion referring to any geologic body that cuts discordantly across* planar wall rock structures, such as bedding or foliation...
intrusion of mantle-derived magmas can likely be attributed to the close proximity of the Alpine fault
Alpine Fault
The Alpine Fault is a geological fault, more specifically known as a right-lateral strike-slip fault, that runs almost the entire length of New Zealand's South Island. It forms a transform boundary between the Pacific Plate and the Indo-Australian Plate. Earthquakes along the fault, and the...
plate boundary across South Island, New Zealand.