Priderite - (K,Ba)(Ti,Fe3+)8O16

For Rex Tregilgas Prider, Professor of Geology at the University of Western Australia, Priderite is a very rare mineral, found principally in lamproitic leucite-bearing rocks. Preiderite was initially identified as rutile, but Norrish (1951) shown to be a new mineral. Priderites are members of the Hollandite group of minerals. The general formula for priderites group of minerals is:

(A)1-2(B)1-2(C)7-6O16

Where A=K,Ba,Cs; B=Fe,Cr,Al,V,Ce; C=Ti,Nb

They consist of paired chain of edge-sharing (B,C)O6 octahedra extending along the c-axis. The chain are linked along their margins to form a framework with continuous tunnels aligned along the c-axis. The tunnels are filled by A-site cations to varying degree. Preiderite play a key role in lamproite recognition as its occurrence is essentially restricted to this paragenesis. Priderite typically forms euhedral small tetragonal crystals with high relief and birefringence, sometime masked by mineral color.

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
madupiteamerica(10).jpg

Small, brown priderite crystals in a madupite (lamproite) from Leucite Hills, Wyoming, USA. PPL image , 10x (Field of view = 2mm)		 priderite(2).jpg

Small, brown priderite crystals in a madupite (lamproite) from Leucite Hills, Wyoming, USA. PPL image , 2x (Field of view = 7mm)		 priderite(3).jpg

Small, brown priderite crystals in a madupite (lamproite) from Leucite Hills, Wyoming, USA. PPL image , 2x (Field of view = 7mm)
priderite(5).jpg

Small, brown priderite crystals in a madupite (lamproite) from Leucite Hills, Wyoming, USA. PPL image , 2x (Field of view = 7mm)		 priderite(4).jpg

Small, brown priderite crystals in a madupite (lamproite) from Leucite Hills, Wyoming, USA. PPL image , 10x (Field of view = 2mm)