Information about Phosphorite
- ''Not to be confused with appetite, the desire to eat.
| Apatite | |
|---|---|
) | |
| General | |
| Category | Phosphate mineral group |
| Chemical formula | Ca5(PO4)3(F,Cl,OH) |
| Identification | |
| Color | Transparent to translucent, usually green, less often colorless, yellow, blue to violet, pink, brown.[1] |
| Crystal habit | Tabular, prismatic crystals, massive, compact or granular |
| Crystal system | Hexagonal Dipyramidal (6/m)[2] |
| Cleavage | [0001] Indistinct, [1010] Indistinct[2] |
| Fracture | Conchoidal to uneven[1] |
| Mohs Scale hardness | 5[1] |
| Luster | Vitreous[1] to subresinous |
| Polish luster | Vitreous[1] |
| Refractive index | 1.634 - 1.638 (+.012, -.006)[1] |
| Optical Properties | Double refractive, uniaxial negative[1] |
| Birefringence | .002-.008[1] |
| Dispersion | .013[1] |
| Pleochroism | Blue stones - strong, blue and yellow to colorless. Other colors are weak to very weak.[1] |
| Ultraviolet fluorescence | Yellow stones - purplish pink which is stronger in long wave; blue stones - blue to light blue in both long and short wave; green stones - greenish yellow which is stronger in long wave; violet stones - greenish yellow in long wave, light purple in short wave.[1] |
| Streak | White |
| Specific gravity | 3.16 - 3.22[2] |
| Diaphaneity | Transparent to translucent[2] |
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, and chlorapatite, named for high concentrations of OH-, F-, or Cl- ions, respectively, in the crystal. The formula of the admixture of the three most common endmembers is written as Ca5(PO4)3(OH, F, Cl), and the formulae of the individual minerals are written as Ca5(PO4)3(OH), Ca5(PO4)3F and Ca5(PO4)3Cl, respectively.
Apatite is one of few minerals that are produced and used by biological micro-environmental systems. Hydroxylapatite is the major component of tooth enamel. 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. For this reason, toothpaste typically contain a source of fluoride anions (e.g. sodium fluoride, sodium monofluorophosphate). Similarly, fluoridated water, allows exchange in the teeth of fluoride ions for hydroxy groups in apatite. Too much fluoride results in dental fluorosis and/or skeletal fluorosis.
In the United States, apatite is often used to fertilize tobacco. It partially starves the plant of nitrogen, which gives American cigarettes a different taste from those of other countries.
Fission tracks in apatite are commonly used to determine the thermal history of orogenic (mountain) belts and of sediments in sedimentary basins.
Phosphorite is the name given to impure, massive apatite.
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.[3] Crystals of rutile may have grown in the crystal of apatite so when 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, Czechoslovakia, Germany, India, Madagascar, Mozambique, Norway, South Africa, Spain, Sri Lanka, and the US.See also
)
Apatite Crystal, Mexico
References
1. ^ Gemological Institute of America, GIA Gem Reference Guide 1995, ISBN 0-87311-019-6
2. ^ [1] Webmineral data
3. ^ Streeter, Edwin W., Precious Stones and Gems 6th edition, George Bell and Sons, London, 1898, p306
2. ^ [1] Webmineral data
3. ^ Streeter, Edwin W., Precious Stones and Gems 6th edition, George Bell and Sons, London, 1898, p306
Further reading
- Schmittner Karl-Erich and Giresse Pierre, 1999. Micro-environmental controls on biomineralization: superficial processes of apatite and calcite precipitation in Quaternary soils, Roussillon, France. Sedimentology 46/3: 463-476.
For the mineral, see .
The appetite is the desire to eat food, felt as hunger. Appetite exists in all higher lifeforms, and serves to regulate adequate energy intake to maintain metabolic needs...... Click the link for more information.
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Transparency is the property of allowing the transmission of light through a material. It is the noun form of the word transparent (for example, glass is usually transparent.
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In optics, transparency is the material property of allowing light to pass through. In mineralogy, another term for this property is diaphaneity. The opposite property is opacity. Transparent materials are clear: they can be seen through.
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habit of crystals.
The many terms used by mineralogists to describe crystal habits are useful in communicating what specimens of a particular mineral often look like. Recognizing numerous habits helps a mineralogist to identify a large number of minerals.
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The many terms used by mineralogists to describe crystal habits are useful in communicating what specimens of a particular mineral often look like. Recognizing numerous habits helps a mineralogist to identify a large number of minerals.
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A crystal system is a category of space groups, which characterize symmetry of structures in three dimensions with translational symmetry in three directions, having a discrete class of point groups.
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hexagonal crystal system is one of the 7 lattice point groups (see Hexagonal_lattice). It has the same symmetry as a right prism with a hexagonal base. There is only one hexagonal Bravais lattice, which has six atoms per unit cell.
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Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite planes, creating smooth surfaces, of which there are several named types:
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- Basal cleavage: cleavage parallel to the base of a crystal, or to the plane of the lateral axes.
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fracture is the (local) separation of a body into two, or more, pieces under the action of stress.
The word fracture is often applied to bones of living creatures, or to crystals or crystalline materials, such as gemstones or metal.
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The word fracture is often applied to bones of living creatures, or to crystals or crystalline materials, such as gemstones or metal.
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The Mohs scale of mineral hardness characterizes the scratch resistance of various minerals through the ability of a harder material to scratch a softer material. It was created in 1812 by the German mineralogist Friedrich Mohs and is one of several definitions of hardness in
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For other senses of this word, see lustre.
Lustre (American English: luster) is a description of the way light interacts with the surface of a crystal, rock, or mineral.
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The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. For example, typical glass has a refractive index of 1.
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Birefringence, or double refraction, is the decomposition of a ray of light into two rays (the ordinary ray and the extraordinary ray) when it passes through certain types of material, such as calcite crystals or boron nitride, depending on the polarization of
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dispersion is the phenomenon that the phase velocity of a wave depends on its frequency.[1] In a prism, dispersion causes the spatial separation of a white light into spectral components of different wavelengths.
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Fluorescence is a luminescence that is mostly found as an optical phenomenon in cold bodies, in which the molecular absorption of a photon triggers the emission of another photon with a longer wavelength.
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The streak (also called powder color) of a mineral is the color of the powder produced when it is dragged across an unweathered surface. Unlike the apparent color of a mineral, which for most minerals can vary considerably, the trail of finely ground powder generally has a
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Phosphate minerals are those minerals that contain the tetrahedrally coordinated phosphate (PO43-) anion along with the freely substituting arsenate (AsO43-) and vanadate (VO43-).
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Hydroxylapatite, also often incorrectly called hydroxyapatite, is a mineral. It is a naturally occurring form of calcium apatite with the formula Ca5(PO4)3(OH), but is usually written Ca10(PO4)6
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Fluorapatite, often with the alternate spelling of fluoroapatite, is a mineral with the formula Ca5(PO4)3F (calcium halophosphate). Fluorapatite is a hard crystalline solid.
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- ''Not to be confused with appetite, the desire to eat.
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, and chlorapatite, named for high concentrations of OH-, F-, or Cl-
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Hydroxyl in chemistry stands for a molecule consisting of an oxygen atom and a hydrogen atom connected by a covalent bond. The neutral form is a hydroxyl radical and the hydroxyl anion is called a hydroxide.
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100% F is stable with 10 neutrons
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1, 3, 5, 7
(strongly acidic oxide)
Electronegativity 3.16 (Pauling scale)
Ionization energies
(more) 1st: 1251.2 kJmol−1
2nd: 2298 kJmol−1
3rd: 3822 kJmol−1
Atomic radius 100 pm
Atomic radius (calc.
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(strongly acidic oxide)
Electronegativity 3.16 (Pauling scale)
Ionization energies
(more) 1st: 1251.2 kJmol−1
2nd: 2298 kJmol−1
3rd: 3822 kJmol−1
Atomic radius 100 pm
Atomic radius (calc.
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ion is an atom or molecule which has lost or gained one or more electrons, making it positively or negatively charged. A negatively charged ion, which has more electrons in its electron shells than it has protons in its nuclei, is known as an anion
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CRYSTAL is a quantum chemistry ab initio program, designed primarily for calculations on crystals (3 dimensions), slabs (2 dimensions) and polymers (1 dimension) using translational symmetry, but it can be used for single molecules.[1] It is written by V.R. Saunders, R.
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An endmember in mineralogy is a mineral that is at the extreme end of a mineral series in terms of purity. Minerals often can be described as solid solutions with varying compositions of some chemical elements, rather than as substances with an exact chemical formula.
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Calcium (IPA: /ˈkalsiəm/) is the chemical element in the periodic table that has the symbol Ca and atomic number 20. It has an atomic mass of 40.078.
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A phosphate, in inorganic chemistry, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Phosphates are important in biochemistry and biogeochemistry.
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