Rosenbuschite - Na₆Ca₆Zr₃Ti(Si₂O₇)₄O₂F₆

Named after Karl Harry Ferdinand Rosenbusch, mineralogist and petrologist at Heidelberg University. One of the most important developers of petrography. Rosenbuschite is one of the numerous mineral species named by Brøgger (1887) and described in full detail in his great work on the minerals of the syenite-pegmatites of southern Norway. This rare mineral occurs in sparse pale-orange patches of close-packed parallel to divergent fibres and needles embedded in coarsely crystallized pegmatite at Langesundsfjord (Larvik, Vestfold, Norway). The rosenbuschite group minerals are Na, Ca-rich titanosilicates, normally occurring in alkaline rocks. The group shows a wide compositional variability hosting a large number of elements. Besides Si the group contains the cations Na, Ca, Y, Mn, Fe, Ti, Mg, Zr, Nb, and REE, which occur in various concentrations

Optical Properties:

• Habits: Prismatic to acicular, radial fibrous, feltlike, massive.
• Color: Usually pale yellow.
• Birefringence: Low, II order.

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Grennaite with acicular rosenbuschite crystals. Norra Kärr Alkaline complex, Sweden. From: Hildegard Wilske

Grennaite with acicular rosenbuschite crystals. Norra Kärr Alkaline complex, Sweden. From: Hildegard Wilske

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.
• 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
Rosenbuschite (small beige crystals), arfvedsonite (green), eudyalite (high relief, white-pale-pink) and feldspar (colorless). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)	Rosenbuschite, eudyalite (very low interference colors), arfvedsonite and feldspar. Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 10x (Field of view = 2mm)	Rosenbuschite (small beige crystals), arfvedsonite (green) and feldspar (colorless). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)
Rosenbuschite, arfvedsonite and feldspar. Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 10x (Field of view = 2mm)	Rosenbuschite (small beige crystals), arfvedsonite (green) and feldspar (colorless). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)	Rosenbuschite, arfvedsonite and feldspar. Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 10x (Field of view = 2mm)
Rosenbuschite (small beige crystals), eudyalite (high relief, white-pale-pink) and feldspar (colorless). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)	Rosenbuschite, eudyalite (very low interference colors) and feldspar. Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 10x (Field of view = 2mm)	Rosenbuschite (small beige crystals), eudyalite (high relief, white-pale-pink) and feldspar (colorless). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)
Fibrous rosenbuschite crystal (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)	Fibrous rosenbuschite crystal (yellow birefringence coloros). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 2x (Field of view = 7mm)	Prismatic rosenbuschite crystals (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)
Prismatic rosenbuschite crystal (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)	Prismatic rosenbuschite crystal (gray birefringence coloros). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 10x (Field of view = 2mm)	Prismatic rosenbuschite crystal (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)
Fibrous rosenbuschite crystal (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)	Fibrous rosenbuschite crystal (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 2x (Field of view = 7mm)	Fibrous rosenbuschite crystal (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 10x (Field of view = 2mm)
Fibrous rosenbuschite crystal (gray birefringence coloros). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 10x (Field of view = 2mm)	Fibrous rosenbuschite crystal (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 20x (Field of view = 1mm)	Fibrous rosenbuschite crystal (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 20x (Field of view = 1mm)
Fibrous rosenbuschite crystals (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 20x (Field of view = 1mm)	Fibrous rosenbuschite crystals (beige in color). Lakarpite from Norra Kärr alkaline complex, Sweden. PPL image, 20x (Field of view = 1mm)	Fibrous rosenbuschite crystals (yellow birefringence coloros). Lakarpite from Norra Kärr alkaline complex, Sweden. XPL image, 20x (Field of view = 1mm)