Kaxtorpite

Lakarpite: A local name for a coarse-grained, sometimes schistose, variety of nepheline syenite consisting of alkali feldspar, nepheline, alkali amphibole (eckermannite) with or without pectolite and aegirine.

Kaxtorpites occurs at the center of the Norra Kärr complex and are melanocratic nepheline syenites, which are foliated and commonly folded. The rock type was named after the farm Kaxtorp. It is made up mainly of nepheline, microcline, albite, eckermannite, aegirine, and catapleiite. Pectolite and lorenzenite occur frequently, as well as secondary zeolite minerals. Willemite, normally a secondary mineral after sphalerite, is an accessory mineral in the kaxtorpite, but sphalerite has at present not been identified in this unit, although it has been observed elsewhere.

For more information about the Norra Kärr complex, see page: "Norra Kärr"

Sample kindly given to me by Axel S.L. Sjöqvist.

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Panoramic view of a kaxtorpite. Image by Andy Tindle (Virtual Microscope). PPL image, field of view = 2.5cm.




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Panoramic view of a kaxtorpite. Image by Andy Tindle (Virtual Microscope). XPL image, field of view = 2.5cm.




Bibliography



• Sjöqvist, A.S.L., Cornell, D.H., Andersen, T., Erambert, M., Ek, M., and Leijd, M. (2013). Three compositional varieties of rare-earth element ore: Eudialyte-group minerals from the Norra Kärr alkaline complex, southern Sweden. Minerals, 3(1), pp.94–120.
• Thesis (2015). Axel S.L. Sjöqvist: Agpaitic rocks of the Norra Kärr alkaline complex: Chemistry, origin, and age of eudialyte-hosted zirconium and rare-earth element ore.
• Saxon, M., Leijd, M., Forrester, K., and Berg, J., (2015): Geology, mineralogy, and metallurgical processing of the Norra Kärr heavy REE deposit, Sweden. In: Simandl, G.J. and Neetz, M., (Eds.), Symposium on Strategic and Critical Materials Proceedings, November 13-14, 2015, Victoria, British Columbia. British Columbia Ministry of Energy and Mines, British Columbia Geological Survey Paper 2015-3, pp. 97-107.


Photo
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Nepheline (colorless) and pectolite crystals (light brown) in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
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Nepheline (I order gray-white) and pectolite crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
kaxtorpite(5).jpg

Big alkali feldspar crystal surrounded by nepheline (colorless) and pectolite crystals (light brown) in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
kaxtorpite(6).jpg

Big alkali feldspar crystal surrounded by nepheline (I order gray-white) and pectolite crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
kaxtorpite(7).jpg

Big alkali feldspar crystal surrounded by nepheline (colorless), pectolite and green fibrous aegirine crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
kaxtorpite(8).jpg

Big alkali feldspar crystal surrounded by nepheline (I order gray-white) pectolite and fibrous aegirine crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
kaxtorpite(9).jpg

Big alkali feldspar crystal surrounded by nepheline (colorless), pectolite (light brown) and green fibrous aegirine crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
kaxtorpite(10).jpg

Big alkali feldspar crystal surrounded by nepheline (I order gray-white) pectolite and fibrous aegirine crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
kaxtorpite(12).jpg

Alkali feldspar crystals surrounded by nepheline (colorless), pectolite (light brown) and green fibrous aegirine crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
kaxtorpite(13).jpg

Alkali feldspar crystals surrounded by nepheline (I order gray-white) pectolite and fibrous aegirine crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
kaxtorpite(14).jpg

Alkali feldspar crystals surrounded by nepheline (colorless), pectolite (light brown) and green fibrous aegirine crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
kaxtorpite(15).jpg

Alkali feldspar crystals surrounded by nepheline (I order gray-white) pectolite and fibrous aegirine crystals in a schistose kaxtorpite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)