Fluorite - CaF2

Fluorite is a halide mineral with formula CaF2; Named in 1797 by Carlo Antonio Galeani Napione from the Latin, fluere = "to flow" (for its use as a flux in steel and aluminum processing). The term fluorescence is derived from fluorite, which will often markedly exhibit this effect. The element fluorine also derives its name from fluorite, a major source for the element. The color of the fluorite has always been a matter of debate, but recent studies have shown that certain elements such as rare earths determine specific color:

Y = blue; Y+ Ce = green-yellow; YO2 = pink; O3 = yellow; Sm2+ = green


Fluorite is a late-stage mineral in granite and other magmatic acid rocks; fluorite usually crystallize at low temperatures (around 500°C). in late-stage pneumatolitic or in skarn deposits fluorite occurs with cassiterite, calcite, sulphides and other minerals.

Optical properties:

• Color: Usually colorless.
• Form: Usually found as euhedral crystals, usually cube, or octahedrons.
• Relief: High.
• Cleavage: Perfect Octahedral; Four direction are distinctive and commonly produce fragments as trigonal pyramids or triangular shapes.
• Interference colors: Isotropic.

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Violet fluorite crystals in a granite. St Austell, UK. Immagine tratta da Virtual Microscope website



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Violet fluorite crystals in a granite. St Austell, UK. Immagine tratta da Virtual Microscope website





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
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Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)		 lakarpite(2).jpg

Arfvedsonite, feldspar and nepheline (gray), fluorite (isotropic). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)		 lakarpite(5).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)
lakarpite(7).jpg

Arfvedsonite, feldspar and nepheline (gray), fluorite (isotropic). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)		 lakarpite(8).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)		 lakarpite(9).jpg

Arfvedsonite, feldspar and nepheline (gray), fluorite (isotropic). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)
lakarpite(7).jpg

Arfvedsonite, feldspar and nepheline (gray), fluorite (isotropic). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)		 lakarpite(8).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)		 lakarpite(9).jpg

Arfvedsonite, feldspar and nepheline (gray), fluorite (isotropic). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)
lakarpite(14).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). In the right corner there is a fibrous rosenbuschite crystal (beige color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)		 lakarpite(15).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). In the right corner there is a fibrous rosenbuschite crystal (beige color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)		 lakarpite(16).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). To the right there are some fibrous rosenbuschite crystals (beige color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
lakarpite(18).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)		 lakarpite(19).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)		 lakarpite(20).jpg

Arfvedsonite, feldspar and nepheline (gray), fluorite (isotropic). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
lakarpite(29).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)		 lakarpite(31).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)		 lakarpite(32).jpg

Arfvedsonite, feldspar and nepheline (gray), fluorite (isotropic). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 10x (Field of view = 2mm)
lakarpite(38).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)		 lakarpite(39).jpg

Arfvedsonite, feldspar and nepheline (gray), fluorite (isotropic). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 10x (Field of view = 2mm)		 lakarpite(46).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)
lakarpite(49).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)		 lakarpite(50).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)		 lakarpite(51).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)
lakarpite(52).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)		 lakarpite(56).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)		 lakarpite(57).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)
lakarpite(58).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)		 lakarpite(60).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)		 lakarpite(64).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)
lakarpite(66).jpg

Arfvedsonite (green), feldspar and nepheline (colorless), fluorite (violet). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)