Fundamental Minerals

Sialic Minerals

Feldspars

Feldspathoids

Quartz

Femic Minerals

Spodumene

Accessory Minerals

Rare Accessory

Alteration Products

Microstructures

Rocks

Jacupiranga complex

Lorenzenite - Na₂Ti₂(Si₂O₆)O₃

Lorenzenite was first identified in 1897 in rock samples from Narsarsuk in Greenaland, and it was named in honor of Danish mineralogist Johannes Theodor Lorenzen. The crystal structure of lorenzenite was solved by Sundberg in 1987 and is described as pyroxene-type (Si₂O₆) chains running in the direction of the b-axis. The TiO₆ octahedra lie in two adjacent layers, alternating in each layer with chains of NaO₇ polyhedra. Lorenzenite is an uncommon mineral that occurs in nepheline syenites and pegmatites in association with aegirine, nepheline, microcline, arfvedsonite, elpidite, loparite, eudialyte, astrophyllite, Mg-neptunite, lavenite, rinkite, apatite, titanite and ilmenite.

Optical Properties:

• Habit: Equant, bladed prismatic to needlelike crystals.
• Color: Pale purple-brown, pale pink to mauve.
• Pleochroism: Weak, pale reddish yellow, yellowish brown to light brown.
• Cleavage: Distinct on 010.
• Relief: Very High.
• Interference colors: High. Very similar to those of titanite.

Brown lorenzenite crystal from Lovozero, Russia. From Michael Wolf.

Sample kindly given to me by Miłosz Huber

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
Euhedral lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Euhedral lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)
Euhedral lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and large K-feldspar crystal (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)
Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)
Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)
Lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)
Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)
Lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)
Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar crystals (colorless) in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (high birefringence), aegirine and feldspar crystals (grey birefringence) in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)
Lorenzenite (brown), green aegirine, feldspar (colorless) and eudialyte (high relief, pale-pink) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine, feldspar (grey birefringence) and eudialyte (isotropic) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine, feldspar (colorless) and eudialyte (high relief, pale-pink) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)
Lorenzenite (brown), green aegirine, feldspar (grey birefringence) and eudialyte (isotropic) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine, feldspar (colorless) and eudialyte (high relief, pale-pink) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine, feldspar (grey birefringence) and eudialyte (isotropic) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)
Lorenzenite (brown), green aegirine and feldspar (grey birefringence) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 2x (Field of view = 7mm)	Lorenzenite (brown), green aegirine and feldspar (colorless) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. PPL image, 10x (Field of view = 2mm)	Lorenzenite (brown), green aegirine and feldspar (grey birefringence) crystals in a syenite from Mount Flora, Lovozero, Kola, Russia. XPL image, 10x (Field of view = 2mm)