APATITE[MINERAL]
Listing description
Apatite is a group of phosphate
minerals, usually referring to hydroxylapatite, fluorapatite and chlorapatite, with high concentrations of OH−, F− and Cl− ions, respectively, in the crystal. The formula of the admixture of the four most common endmembers is written as Ca10(PO4)6(OH,F,Cl)2, and the
crystal unit cell formulae of the individual minerals are written as Ca10(PO4)6(OH)2,
Ca10(PO4)6(F)2and Ca10(PO4)6(Cl)2.
Detailed description
The mineral was named apatite by the German geologist Abraham Gottlob Werner in 1786, although the specific mineral he
had described was reclassified as fluorapatite in 1860 by the German mineralogist Karl Friedrich August
Rammelsberg. Apatite is derived from the Greek απατείν (apatein), which
means to deceive or to be misleading, as it was often mistaken for other
minerals.[3]
Apatite is one of a few minerals produced and used by biological
micro-environmental systems. Apatite is the defining mineral for 5 on the Mohs
scale. Hydroxyapatite, also known as hydroxylapatite, is the major
component of tooth
enamel and bone
mineral. A relatively rare form of apatite in which most of the OH
groups are absent and containing many carbonate and acid phosphate
substitutions is a large component of bone material.
Fluorapatite (or fluoroapatite) is more resistant to acid attack
than is hydroxyapatite; in the mid-20th century, it was discovered that
communities whose water supply naturally contained fluorine had lower rates of
dental caries.[4] Fluoridated
water allows
exchange in the teeth of fluoride ions for hydroxyl
groups in
apatite. Similarly, toothpaste typically contains a source of fluoride anions (e.g. sodium fluoride, sodium monofluorophosphate). Too
much fluoride results in dental
fluorosis and/or skeletal fluorosis.
Fission tracks in
apatite are commonly used to determine the thermal history of orogenic
(mountain) belts and of sediments in sedimentary
basins. (U-Th)/He
dating of
apatite is also well established for use in determining thermal histories and
other, less typical applications such as paleo-wildfire dating.
Phosphorite is a
phosphate-rich sedimentary
rock, that contains between 18% and 40% P2O5.
The apatite in phosphorite is present as cryptocrystalline masses referred to as collophane.
Uses
The primary use of apatite is in the manufacture of
fertilizer – it is a source of phosphorus. It is occasionally used as a
gemstone. Green and blue varieties in finely divided form, are pigments with
excellent covering power.
During digestion of apatite with sulfuric acid to make
phosphoric acid, hydrogen
fluoride is
produced as a byproduct from any fluorapatite content.
This byproduct is a minor industrial source of hydrofluoric
acid.[5]
Fluoro-chloro apatite forms the basis of the now obsolete
Halophosphor fluorescent tube phosphor system. Dopant elements of manganese and
antimony, at less than one mole-percent, in place of the calcium and phosphorus
impart the fluorescence, and adjustment of the fluorine to chlorine ratio
adjusts the shade of white produced. Now almost entirely replaced by the
Tri-Phosphor system.[6]
In the United
States, apatite derived fertilizers are used to supplement the
nutrition of many agricultural crops by providing a valuable source of phosphate.
Apatites are also a proposed host material for storage of nuclear
waste, along with other phosphates.
Gemology
Apatite is infrequently used as a gemstone. Transparent stones
of clean color have been faceted, and chatoyant specimens have been cabochon cut.[1]Chatoyant
stones are known as cat's-eye
apatite,[1]transparent
green stones are known as asparagus
stone,[1] and blue stones have been called moroxite.[7] If crystals of rutile have grown in the
crystal of apatite, in the right light the cut stone displays a cat's eye
effect. Major sources for gem apatite are[1] Brazil, Burma, and Mexico. Other
sources include[1] Canada, Czech
Republic, Germany, India, Madagascar, Mozambique, Norway, South
Africa, Spain, Sri Lanka, and
the United States.
Use as an ore mineral
Apatite is occasionally found to contain significant amounts of rare-earth elements and can
be used as an ore for those metals. This
is preferable to traditional rare earth ores, as apatite is non-radioactive and does not pose an environmental
hazard in mine
tailings. However, some apatite in Florida used to produce phosphate for
agriculture does contain uranium, radium, lead 210 and polonium 210 and radon.
Apatite is an ore mineral at the Hoidas Lake rare
earth project.
PRICE
$44/KG OR
$20/IB
For more information:
mobile: +2348039721941
contact person: emeaba uche
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