Ekerite

Ekerite: A local name for a peralkaline granite containing anorthoclase microperthite and small amounts of arfvedsonite and aegirine. (the name ekerite was given by Brøgger in 1880 after lake Eikeren pluton, Norway). The rock can be classified as alkali granite in modern terminology with riebeckite and arfvedsonite amphiboles. The Gjerdingen ekerite is located about 1 km east of the Lake Gjerdingen, and consists as small outcrops on the road from Lake Gjerdingen, close to Gjerdingenelva river.

Sample doned by Pietro Vignola (University of Milan, Italy).

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
Alkali feldspar (alterd by Sericite), quarz (colorless) and yellow Gjerdingenite (a rare Nb-Ti silicate mineral). Ekerite from Gjerdingen, Norway. PPL image, 2x (Field of view = 7mm)	Alkali feldspar (alterd by Sericite), quarz and Gjerdingenite (a rare Nb-Ti silicate mineral). Ekerite from Gjerdingen, Norway. XPL image, 2x (Field of view = 7mm)	Alkali feldspar (alterd by Sericite), quarz (colorless) and green pyroxene crystals. Ekerite from Gjerdingen, Norway. PPL image, 2x (Field of view = 7mm)
Alkali feldspar (alterd by Sericite), quarz and pyroxene crystals. Ekerite from Gjerdingen, Norway. XPL image, 2x (Field of view = 7mm)	Alkali feldspar (alterd by Sericite), quarz (colorless) and green pyroxene crystals. Ekerite from Gjerdingen, Norway. PPL image, 2x (Field of view = 7mm)	Alkali feldspar (alterd by Sericite) and quarz (colorless). Ekerite from Gjerdingen, Norway. PPL image, 2x (Field of view = 7mm)
Alkali feldspar (alterd by Sericite) and quarz. Ekerite from Gjerdingen, Norway. XPL image, 2x (Field of view = 7mm)	Alkali feldspar (alterd by Sericite), quarz (colorless) and green pyroxene crystals. Ekerite from Gjerdingen, Norway. PPL image, 2x (Field of view = 7mm)	Alkali feldspar (alterd by Sericite), quarz and pyroxene crystals. Ekerite from Gjerdingen, Norway. XPL image, 2x (Field of view = 7mm)
Alkali feldspar (alterd by Sericite) and quarz (colorless). Ekerite from Gjerdingen, Norway. PPL image, 2x (Field of view = 7mm)	Alkali feldspar (alterd by Sericite), quarz (colorless) and green pyroxene crystals. Ekerite from Gjerdingen, Norway. PPL image, 2x (Field of view = 7mm)	Alkali feldspar (alterd by Sericite), quarz and pyroxene crystals. Ekerite from Gjerdingen, Norway. XPL image, 2x (Field of view = 7mm)
Alkali feldspar (alterd by Sericite), quarz (colorless) and yellow Gjerdingenite (a rare Nb-Ti silicate mineral). Ekerite from Gjerdingen, Norway. PPL image, 10x (Field of view = 2mm)	Alkali feldspar (alterd by Sericite), quarz and Gjerdingenite (a rare Nb-Ti silicate mineral). Ekerite from Gjerdingen, Norway. XPL image, 10x (Field of view = 2mm)	Yellow Gjerdingenite (a rare Nb-Ti silicate mineral) crystal. Ekerite from Gjerdingen, Norway. PPL image, 20x (Field of view = 1mm)