Pulaskite

Pulaskite: A variety of nepheline-bearing alkali feldspar syenite containing alkali feldspar and varying amounts of sodic pyroxenes and amphiboles, fayalite, biotite and minor amounts of nepheline. Name from Pulaski County, Arkansas, USA.

Pulaskite occurs mainly along the western and northern contacts of the Norra Kärr intrusion. It is a medium-coarse grained rock low in REEs and typically carries large rounded microcline augen in a groundmass of albite, aegirine, amphibole, microcline and minor biotite and nepheline. Rosenbuschite, apatite, titanite and fluorite occur as accessories.

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

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

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
pulaskite(1).jpg

Alkali feldspar (colorless) in a fine-grained groundmass of aegirine (green), microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)
pulaskite(2).jpg

Alkali feldspar (with Perthite unmixing) in a fine-grained groundmass of aegirine, microcline and nepheline (I order white-gray). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)
pulaskite(3).jpg

Alkali feldspar (colorless) in a fine-grained groundmass of aegirine (green), microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)
pulaskite(4).jpg

Alkali feldspar (with Perthite unmixing) in a fine-grained groundmass of aegirine, microcline and nepheline (I order white-gray). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)
pulaskite(5).jpg

Alkali feldspar (colorless) in a fine-grained groundmass of aegirine (green), microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)
pulaskite(6).jpg

Alkali feldspar (with Perthite unmixing) in a fine-grained groundmass of aegirine, microcline and nepheline (I order white-gray). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)
pulaskite(7).jpg

Alkali feldspar (colorless) in a fine-grained groundmass of aegirine (green), microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 1x (Field of view = 9mm)
pulaskite(8).jpg

Alkali feldspar (with Perthite unmixing) in a fine-grained groundmass of aegirine, microcline and nepheline (I order white-gray). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)
pulaskite(9).jpg

Alkali feldspar (with Perthite unmixing) in a fine-grained groundmass of aegirine, microcline and nepheline (I order white-gray). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 1x (Field of view = 9mm)
pulaskite(10).jpg

Alkali feldspar (colorless) in a fine-grained groundmass of aegirine (green), microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
pulaskite(11).jpg

Alkali feldspar (with Perthite unmixing) in a fine-grained groundmass of aegirine, microcline and nepheline (I order white-gray). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
pulaskite(12).jpg

Alkali feldspar (colorless) in a fine-grained groundmass of aegirine (green), microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
pulaskite(13).jpg

Alkali feldspar (with Perthite unmixing) in a fine-grained groundmass of aegirine, microcline and nepheline (I order white-gray). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
pulaskite(14).jpg

Aegirine crystals in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
pulaskite(15).jpg

Aegirine crystals in a fine-grained groundmass of microcline and nepheline (I order white-gray). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
pulaskite(16).jpg

Aegirine crystals (green) and sodic amphiboles (green-blue) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
pulaskite(17).jpg

Aegirine crystals (high interference colors) and sodic amphiboles (low interference colors) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
pulaskite(18).jpg

Aegirine crystals (green) and sodic amphiboles (green-blue) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
pulaskite(19).jpg

Aegirine crystals (high interference colors) and sodic amphiboles (low interference colors) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
pulaskite(20).jpg

Aegirine crystals (green) and sodic amphiboles (green-blue) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
pulaskite(21).jpg

Aegirine crystals (green) and sodic amphiboles (green-blue) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
pulaskite(22).jpg

Aegirine crystals (high interference colors) and sodic amphiboles (low interference colors) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)
pulaskite(25).jpg

Aegirine crystals (green) and sodic amphiboles (green-blue) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
pulaskite(26).jpg

Aegirine crystals (high interference colors) and sodic amphiboles (low interference colors) in a fine-grained groundmass of microcline and nepheline (colorless). Pulaskite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)