Pollucite
Encyclopedia
Pollucite is a zeolite
mineral with the formula (Cs,Na
)2Al2Si
4O
12·2H2O
with iron
, calcium
, rubidium
and potassium
as common substituting elements. It is important as a significant ore of caesium
and sometimes rubidium
. It forms a solid solution series with analcime. It crystallizes in the isometric - hexoctahedral crystal system as colorless, white, gray, or rarely pink and blue masses. Well formed crystals are rare. It has a Mohs hardness of 6.5 and a specific gravity of 2.9. It has a brittle fracture and no cleavage.
Its typical occurrence is in lithium-rich granite pegmatite
s in
association with quartz
, spodumene
, petalite
, amblygonite
, lepidolite
, elbaite
, cassiterite
, columbite
, apatite
, eucryptite
, muscovite
, albite
and microcline
.
It was first described by August Breithaupt
in 1846 for occurrences on the island of Elba
, Italy
. It is named for Pollux
, the twin of Castor on the grounds that it is often found associated with petalite
(previously known as castorite). The high caesium content was missed by the first analysis by Karl Friedrich Plattner
in 1848, but after the discovery of caesium in 1860 a second analysis in 1864 was able to show the high caesium content of pollucite.
About 82% of the world's known reserves of pollucite occur near Bernic Lake
in Manitoba, Canada, where they are mined for their caesium content for use in caesium formate oil drilling assistance. This ore is about 20% by weight caesium.
Francium
, an intensely radioactive element related to rubidium and caesium, can occur in minute quantities in certain pollucite ores, because the most stable isotope is Francium-223 with a half-life of 21.8 minutes. Some of the initial and much-disputed discoveries of this element involved the spectral analysis of pollucite, showing unexplained lines attributed by the existence of a new element.
Zeolite
Zeolites are microporous, aluminosilicate minerals commonly used as commercial adsorbents. The term zeolite was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that upon rapidly heating the material stilbite, it produced large amounts of steam from water that...
mineral with the formula (Cs,Na
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
)2Al2Si
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...
12·2H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
with iron
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...
, calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
, rubidium
Rubidium
Rubidium is a chemical element with the symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group. Its atomic mass is 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other elements in group 1, such as very rapid...
and potassium
Potassium
Potassium is the chemical element with the symbol K and atomic number 19. Elemental potassium is a soft silvery-white alkali metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite the hydrogen emitted in the reaction.Potassium and sodium are...
as common substituting elements. It is important as a significant ore of caesium
Caesium
Caesium or cesium is the chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28 °C , which makes it one of only five elemental metals that are liquid at room temperature...
and sometimes rubidium
Rubidium
Rubidium is a chemical element with the symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group. Its atomic mass is 85.4678. Elemental rubidium is highly reactive, with properties similar to those of other elements in group 1, such as very rapid...
. It forms a solid solution series with analcime. It crystallizes in the isometric - hexoctahedral crystal system as colorless, white, gray, or rarely pink and blue masses. Well formed crystals are rare. It has a Mohs hardness of 6.5 and a specific gravity of 2.9. It has a brittle fracture and no cleavage.
Its typical occurrence is in lithium-rich granite 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 in
association with 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,...
, spodumene
Spodumene
Spodumene is a pyroxene mineral consisting of lithium aluminium inosilicate, LiAl2, and is a source of lithium. It occurs as colorless to yellowish, purplish, or lilac kunzite , yellowish-green or emerald-green hiddenite, prismatic crystals, often of great size...
, petalite
Petalite
Petalite, also known as castorite, is a lithium aluminium tectosilicate mineral LiAlSi4O10, crystallizing in the monoclinic system. Petalite is a member of the feldspathoid group. It occurs as colorless, grey, yellow, yellow grey, to white tabular crystals and columnar masses. Occurs in...
, amblygonite
Amblygonite
Amblygonite is a fluorophosphate mineral, AlPO4, composed of lithium, sodium, aluminium, phosphate, fluoride and hydroxide. The mineral occurs in pegmatite deposits and is easily mistaken for albite and other feldspars. Its density, cleavage and flame test for lithium are diagnostic. Amblygonite...
, lepidolite
Lepidolite
Lepidolite Lepidolite Lepidolite (KLi2Al(Al,Si)3O10(F,OH)2 is a lilac-gray or rose-colored phyllosilicate mineral of the mica group that is a secondary source of lithium. It is associated with other lithium-bearing minerals like spodumene in pegmatite bodies. It is one of the major sources of the...
, elbaite
Elbaite
Elbaite, a sodium, lithium, aluminium boro-silicate, is a mineral species belonging to the tourmaline group. Elbaite forms three series, with dravite, with liddicoatite, and with schorl...
, cassiterite
Cassiterite
Cassiterite is a tin oxide mineral, SnO2. It is generally opaque, but it is translucent in thin crystals. Its luster and multiple crystal faces produce a desirable gem...
, columbite
Columbite
Columbite, also called niobite, niobite-tantalite and columbate [2O6], is a black mineral group that is an ore of niobium and tantalum. It has a submetallic luster and a high density and is a niobate of iron and manganese, containing tantalate of iron. This mineral group was first found in Haddam,...
, apatite
Apatite
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH−, F−, Cl− or Br− ions, respectively, in the crystal...
, eucryptite
Eucryptite
Eucryptite is a lithium bearing aluminium silicate mineral with formula LiAlSiO4. It crystallizes in the trigonal - rhombohedral crystal system. It typically occurs as granular to massive in form and may pseudomorphically replace spodumene. It has a brittle to conchoidal fracture and indistinct...
, muscovite
Muscovite
Muscovite is a phyllosilicate mineral of aluminium and potassium with formula KAl22, or 236. It has a highly-perfect basal cleavage yielding remarkably-thin laminæ which are often highly elastic...
, 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...
and microcline
Microcline
Microcline is an important igneous rock-forming tectosilicate mineral. It is a potassium-rich alkali feldspar. Microcline typically contains minor amounts of sodium. It is common in granite and pegmatites. Microcline forms during slow cooling of orthoclase; it is more stable at lower temperatures...
.
It was first described by August Breithaupt
August Breithaupt
Johann Friedrich August Breithaupt was a German mineralogist and professor at Freiberg Mining Academy in Freiberg, Saxony.-Biography:...
in 1846 for occurrences on the island of Elba
Elba
Elba is a Mediterranean island in Tuscany, Italy, from the coastal town of Piombino. The largest island of the Tuscan Archipelago, Elba is also part of the National Park of the Tuscan Archipelago and the third largest island in Italy after Sicily and Sardinia...
, Italy
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
. It is named for Pollux
Castor and Pollux
In Greek and Roman mythology, Castor and Pollux or Polydeuces were twin brothers, together known as the Dioscuri . Their mother was Leda, but Castor was the mortal son of Tyndareus, king of Sparta, and Pollux the divine son of Zeus, who visited Leda in the guise of a swan...
, the twin of Castor on the grounds that it is often found associated with petalite
Petalite
Petalite, also known as castorite, is a lithium aluminium tectosilicate mineral LiAlSi4O10, crystallizing in the monoclinic system. Petalite is a member of the feldspathoid group. It occurs as colorless, grey, yellow, yellow grey, to white tabular crystals and columnar masses. Occurs in...
(previously known as castorite). The high caesium content was missed by the first analysis by Karl Friedrich Plattner
Karl Friedrich Plattner
Karl Friedrich Plattner was a German metallurgical chemist.He was born at Kleinwaltersdorf, near Freiberg in the Electorate of Saxony, on 2 January 1800. His father, though only a poor working miner, found the means to have him educated first at the Bergschule and then at the Bergakademie of...
in 1848, but after the discovery of caesium in 1860 a second analysis in 1864 was able to show the high caesium content of pollucite.
About 82% of the world's known reserves of pollucite occur near Bernic Lake
Bernic Lake
Bernic Lake is a lake in the province of Manitoba, Canada.The Tanco mine is located on the northwestern shore of the river. The mine is an active producer of caesium, tantalum and spodumene from a large pegmatite ore body....
in Manitoba, Canada, where they are mined for their caesium content for use in caesium formate oil drilling assistance. This ore is about 20% by weight caesium.
Francium
Francium
Francium is a chemical element with symbol Fr and atomic number 87. It was formerly known as eka-caesium and actinium K.Actually the least unstable isotope, francium-223 It has the lowest electronegativity of all known elements, and is the second rarest naturally occurring element...
, an intensely radioactive element related to rubidium and caesium, can occur in minute quantities in certain pollucite ores, because the most stable isotope is Francium-223 with a half-life of 21.8 minutes. Some of the initial and much-disputed discoveries of this element involved the spectral analysis of pollucite, showing unexplained lines attributed by the existence of a new element.
External links
- Fontani, Marco (2005-09-10). "The Twilight of the Naturally-Occurring Elements: Moldavium (Ml), Sequanium (Sq) and Dor (Do)". International Conference on the History of Chemistry: 1–8. Retrieved on 2007-04-08.