Apatite group

Two Apatite from Mexic

Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite and chlorapatite with high concentrations of OH, F and Cl negative ions.
Apatite is often mistaken for other minerals, the mane comes from Greek - apateit means to deceive.
Hydroxyapatite is major component of bone mineral.
Fluorapatite is more resistant to acids and the discovery of water that contains fluorine, proves to lower the rate of dental caries because fluoridated water allows exchange in the teeth of fluoride ions for hydroxyl group in apatite. too much fluoride results in dental fluorisis and skeletal fluorisis.
Phosphorite is phosphate rich sedimentary rock that contains between 18% and 40% P2O5 and the apatite in phosphorite is present as cryptocrystalline masses referred to as collophane.
Chatoyant stones are known as cat's eye apatite.
Moon rocks collected during Apollo program contain traces of apatite. Analysis in 2010 reveals water trapped in the mineral as hydroxyl, leads to estimates of water on lunar surface at a rate of at least 64 parts per bilion. If the amount of mineral-locked water was converted to liquid, it would cover the Moon's surface in roughly one meter of water.

Uses:
Fertilizer from the source of phosphorus.
Occasionally as gemstone.
Apatite with sulfuric acid makes phosphoric acid, hydrogen fluoride is produced as a byproduct from any fluorapatite contenti. This byproduct is minor industrial source of hydrofluoric acid.

As ore:
Apatite is the main source of phosphorus.
Apatite occasionally can contain amounts of rare-earth elements and are used as ore for those metals.
Apatite often contains uranium and its equally radioactive decay-chain nuclides.

Characteristics:
Formula Ca5(PO4)3(F,Cl, OH)
39,36% Calcium; 18,25% Phosphorus; 0,06% Hydrogen; 2,32% Chlorine; 38,76% Oxygen; 1,24% Fluorine
Individual Apatite minerals:
Fluorapatite - Calcium fluoro-phosphate Ca5(PO4)3F [39,74% Ca; 17,43% P; 38,07% O; 3,77% F]
Chlorapatite - Calcium chloro-phosphate Ca5(PO4)3Cl [38,48% Ca; 17,84% P; 6,81 Cl; 36,87% O]
Hydroxylapatite - Basic calcium phosphate Ca5(PO4)3OH [39,89% Ca; 18,50% P; 0,20% H; 41,41% O]
Crystal system Hexagonal
Color: transparent to translucent, green, colorless, yellow, blue to violet, pink, brown
Habit: tabular, prismatic, massive, compact or granular
Cleavage indistinct
Fracture: conchoidal to uneven
Hardness 5 Mohs
Streak white
Luster vitreous to subresinous
Specific gravity 3,16-3,22
Density 3,16-3,22
Optical properties: double refractive, unaxial negative
Refractive index 1,634-1,638
Rock type: Igneous, Metamorphic
Special characteristics:
Luminescence: yellow stones have strong purplish pink fluorescence in long wave
blue stones have blue to light blue in both long and short wave UV
green stones have greenish yellow strong in long wave
violet stones have greenish yellow in long wave and light purple in short wave
May be low radioactive and contain uranium
Thermoluminescent bluish-white
Fluorapatite show the most long range of colors in fluorescent light from white, bluish white, yellow, brown, green, purple, violet in long and shortwave with intensity from weak in long wave to strong in short wave UV
Chloroapatite and Hydroxylapatite can show orange yellow fluorescence in long and short wave UV



Tests:
Hardness 5 Mohs; Streak white
Certain localities will have specimens that fluoresce orange yellow in shortwave
Thermoluminescent bluish-white

Varieties:
Hydroxyapatite; white, usually opaque; also known as hydroxylapatite is a major component of tooth enamel and bone mineral; also named Apatite (CaOH) - is a Basic calcium phosphate, Ca5(PO4)3OH
Fluorapatite or fluoroapatite blue, green, brown-pink, colorless; is more resistant to acid than hydroxyapatite and thus water discovered to contain fluorine has a lower rates of dental caries. Fluoridated water allows exchange in the teeth of fluoride ions for hydroxyl group in apatite; too much fluoride results in dental fluorosis and skeletal fluorosis; is a Calcium fluoro-phosphate Ca5(PO4)3F
Chlorapatite - white, green or blue, may be opaque often; is a Calcium chloro-phosphate Ca5(PO4)3Cl
Collophane - microcrystalline variety of botryoidal white Apatite
Carbonate apatite - bariety of Apatite group where the phosphate radical PO is partially replaced by carbonate radiacal CO; has formula Ca5(PO4,CO3)3(OH,F)
Manganapatite - manganiese-rich wariety of Apatite
Sammite - strontium rich form of Apatite containing rare earth elements
Staffelite - botryoidal variety of Apatite
Strontian-Apatite is a rare strontium rich variety of Apatite, with the calcium partially replaced by strontium; formula: (Sr,Ca)5(PO4)3(OH,F)

Common mineral associations: Quartz, Feldspar, Calcite, Magnetite, Muscovite, Phlogopite, Nepheline, Diopside

Distinguishing similar minerals:
Beryl, Tourmaline and Quarts - greater hardness
Calcite - lower hardness, effervescent in acid
Pyromorphite, Mimetite and Vanadinite - Slightly softer and usually occur in distinct localities


Other names: apatit apatitul apatite fluorapatit fluorapatite fluorapatitul fluoroapatit fluoroapatitul fluoroapatite hidroxiapatit hidroxiapatitul hydroxyapatit hydroxyapatitul hydroxiapatit hydroxiapatitul hidroxyapatit hidroxyapatitul cloroapatit cloroapatitul clorapatit clorapatitul chlorapatite