Apatite - Ca5(PO4)2[F, OH, Cl]
Apatite structure is characterized by phosphate oxyanion linked by Ca
2+ cations to forma hexagonal frame-work with F
- anions lying at the corners of hexagonal cell and coordinated by three Ca
2- cations. Composition of the apatite minerals is highly variable and there is a complete solid solution between three end-members, fluoroapatite Ca
5(PO
4)
3F, chloroapatite Ca
5(PO
4)
3Cl and hydroxylapatite Ca
5(PO
4)OH. The dominant anion (F,Cl,OH) determinate the Apatite variety. Apatite is a very common early-formed accessory mineral in nearly all type of igneous rocks. Apatite is also concentrated by late magmatic segregation, and it appears in granite pegmatite.
Optical Properties:
•
Form: Tiny euhedral prismatic crystals elongated on c, with exagonal basal section and rectangular to acicular prismatic section.
•
Relief: High.
•
Color: Colorless.
•
Interference Colors: weak.
•
cleavage: Poor parallel to (001).
Green apatite crystals in a carbonatite. Siilinjärvi, Finland. From sand atlas.
Bibliography
• Cox et al. (1979): The Interpretation of Igneous Rocks, George Allen and Unwin, London.
• Howie, R. A., Zussman, J., & Deer, W. (1992). An introduction to the rock-forming minerals (p. 696). Longman.
• Le Maitre, R. W., Streckeisen, A., Zanettin, B., Le Bas, M. J., Bonin, B., Bateman, P., & Lameyre, J. (2002). Igneous rocks. A classification and glossary of terms, 2. Cambridge University Press.
• Middlemost, E. A. (1986). Magmas and magmatic rocks: an introduction to igneous petrology.
• Shelley, D. (1993). Igneous and metamorphic rocks under the microscope: classification, textures, microstructures and mineral preferred-orientations.
• Vernon, R. H. & Clarke, G. L. (2008): Principles of Metamorphic Petrology. Cambridge University Press.
Photo
![xenolitepirosseniticovulsini(22).jpg](/immagini/vulc/piccole/xenolitepirosseniticovulsini(22).jpg)
Pyroxene in basal section (with colorless apatite inclusions) in a xenolith from Vulsini volcano, Italy. PPL image, 2x (Field of view = 7mm) |
![pyroxene2020(33).jpg](/immagini/pluto/piccole/pyroxene2020(33).jpg)
Pyroxene in basal section (with colorless apatite inclusions) in a xenolith from Vulsini volcano, Italy. PPL image, 10x (Field of view = 2mm) |
![pyroxene2020(34).jpg](/immagini/pluto/piccole/pyroxene2020(34).jpg)
Pyroxene in basal section (with colorless apatite inclusions) in a xenolith from Vulsini volcano, Italy. PPL image, 10x (Field of view = 2mm) |
![sovite(vicente)(13).jpg](/immagini/pluto/piccole/sovite(vicente)(13).jpg)
Calcite, biotite and apatite (I order gray) crystals in a sövite from Sào Vicente island, Cape Verde. XPL image, 1x (Field of view = 9mm) |
![sovite(vicente)(14).jpg](/immagini/pluto/piccole/sovite(vicente)(14).jpg)
Calcite and apatite (high relief, colorless) crystals in a sövite from Sào Vicente island, Cape Verde. PPL image, 1x (Field of view = 9mm) |
![sovite(vicente)(15).jpg](/immagini/pluto/piccole/sovite(vicente)(15).jpg)
Calcite and apatite (I order gray) crystals in a sövite from Sào Vicente island, Cape Verde. XPL image, 1x (Field of view = 9mm) |
![sovite(vicente)(26).jpg](/immagini/pluto/piccole/sovite(vicente)(26).jpg)
Calcite and apatite (I order gray) crystals in a sövite from Sào Vicente island, Cape Verde. XPL image, 2x (Field of view = 7mm) |
![sovite(vicente)(28).jpg](/immagini/pluto/piccole/sovite(vicente)(28).jpg)
Calcite and apatite (high relief, colorless) crystals in a sövite from Sào Vicente island, Cape Verde. PPL image, 2x (Field of view = 7mm) |
![sovite(vicente)(29).jpg](/immagini/pluto/piccole/sovite(vicente)(29).jpg)
Calcite and apatite (I order gray) crystals in a sövite from Sào Vicente island, Cape Verde. XPL image, 2x (Field of view = 7mm) |
![sokli(20).jpg](/immagini/vulc/piccole/sokli(20).jpg)
Phlogopite (brown), calcite, apatite (high relief, colorless) and magnetite (black) crystals in a carbonatite from Sokli carbonatite complex, Finland. PPL image, 1x (Field of view = 9mm) |
![sokli(21).jpg](/immagini/vulc/piccole/sokli(21).jpg)
Phlogopite (high birefringence), calcite, apatite (I order gray) and magnetite crystals in a carbonatite from Sokli carbonatite complex, Finland. XPL image, 1x (Field of view = 9mm) |
![sokli(22).jpg](/immagini/vulc/piccole/sokli(22).jpg)
Phlogopite (brown), calcite, apatite (high relief, colorless) and magnetite (black) crystals in a carbonatite from Sokli carbonatite complex, Finland. PPL image, 1x (Field of view = 9mm) |
![apatitebiotite(2).jpg](/immagini/pluto/piccole/apatitebiotite(2).jpg)
Apatite crystals in biotite. PPL image, 2x (Field of view = 7mm) |
![apatitebiotite(3).jpg](/immagini/pluto/piccole/apatitebiotite(3).jpg)
Apatite crystals in biotite. PPL image, 2x (Field of view = 7mm) |
![apatitebiotite(4).jpg](/immagini/pluto/piccole/apatitebiotite(4).jpg)
Apatite crystals in biotite. PPL image, 2x (Field of view = 7mm) |
![apatitebiotite(5).jpg](/immagini/pluto/piccole/apatitebiotite(5).jpg)
Apatite crystals in biotite. PPL image, 2x (Field of view = 7mm) |
![apatitebiotite(6).jpg](/immagini/pluto/piccole/apatitebiotite(6).jpg)
Apatite crystals in biotite. PPL image, 2x (Field of view = 7mm) |
![apatitebiotite(7).jpg](/immagini/pluto/piccole/apatitebiotite(7).jpg)
Apatite crystals in biotite. PPL image, 2x (Field of view = 7mm) |
![nefelinolite2014)(32).jpg](/immagini/pluto/piccole/nefelinolite2014)(32).jpg)
Apatite crystals (hexagonal basal section) in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(33).jpg](/immagini/pluto/piccole/nefelinolite2014)(33).jpg)
Apatite crystals (hexagonal basal section) in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(34).jpg](/immagini/pluto/piccole/nefelinolite2014)(34).jpg)
Apatite crystals (hexagonal basal section) in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(39).jpg](/immagini/pluto/piccole/nefelinolite2014)(39).jpg)
Apatite crystals (hexagonal basal section) in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(41).jpg](/immagini/pluto/piccole/nefelinolite2014)(41).jpg)
Apatite crystals (hexagonal basal section) in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(42).jpg](/immagini/pluto/piccole/nefelinolite2014)(42).jpg)
Apatite crystals (hexagonal basal section) in augite. XPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(44).jpg](/immagini/pluto/piccole/nefelinolite2014)(44).jpg)
Apatite crystals (hexagonal basal section) in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(46).jpg](/immagini/pluto/piccole/nefelinolite2014)(46).jpg)
Apatite crystals (hexagonal basal section) in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(37).jpg](/immagini/pluto/piccole/nefelinolite2014)(37).jpg)
Apatite crystals in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(38).jpg](/immagini/pluto/piccole/nefelinolite2014)(38).jpg)
Apatite crystals in augite. XPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(37).jpg](/immagini/pluto/piccole/nefelinolite2014)(37).jpg)
Apatite crystals in augite. PPL image, 10x (Field of view = 2mm) |
![nefelinolite2014)(47).jpg](/immagini/pluto/piccole/nefelinolite2014)(47).jpg)
Apatite crystals in augite. PPL image, 10x (Field of view = 2mm) |