Freudenbergite is a

mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

that is named in honor of Wilhelm Freudenberg,

palaeontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of fossi ...

at the

University of Tübingen The University of Tübingen, officially the Eberhard Karl University of Tübingen (german: Eberhard Karls Universität Tübingen; la, Universitas Eberhardina Carolina), is a public research university located in the city of Tübingen, Baden-W� ...

and the

University of Göttingen The University of Göttingen, officially the Georg August University of Göttingen, (german: Georg-August-Universität Göttingen, known informally as Georgia Augusta) is a public research university in the city of Göttingen, Germany. Founded ...

, and curator for mineralogy and geology at the National Collections of Natural History in Karlsruhe. He studied Katzenbuckel rocks. Naturally occurring freudenbergite is a solid solution of two end members Na₂Fe ⁺³₂Ti₆O₁₆ and Na₂Fe ⁺²Ti₇O₁₆, which were referred to as low-Ti and high-Ti freudenbergite, respectively Both varieties were found in the course of close examination of samples from the Katzenbuckel Complex, Germany, in which this mineral was documented for the first time As a possible mineral Fe2+ analog was named UM1983-07-O:FeNaTi

Monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

with straight extinction and high birefringence. Brown. Synthetic freudenbergite was crystallized during the

lamprophyllite Lamprophyllite (named for its lustrous cleavage) is a rare, but widespread mineral Ti-silicate mineral usually found in intrusive agpasitic igneous rocks. Yellow, reddish brown, Vitreous, Pearly. Lamprophyllite formula is (Sr,Ba,K,Na)2Na(Na,Fe, ...

incongruity melting.

References

Bibliography

Haggerty, S.E. (1983): A freudenbergite-related mineral in granulites from a kimberlite in Liberia, West Africa. Neues Jahrb. Mineral. Monatsch.: 375-384; in: Dunn, P.J., Cabri, L.J., Ferraiolo, J.A., Grice, J.D., Jambor, J.L., Mueller, W., Shigley, J.E., Puziewicz, J., Vanko, D.A. (1984): New mineral names. American Mineralogist: 69: 1194 Mysen B. O. , Virgo D. , and Seifert F. A. , “Redox equi? libria of iron in alkaline earth silicate melts: relationships between melt structure, oxygen fugacity, temperature and properties of iron?bearing silicate liquids,” Am. Mineral. 69, 834–847 (1984). Smith, D.G.W., Nickel, E.H. (2007): A System of Codification for Unnamed Minerals: Report of the SubCommittee for Unnamed Minerals of the IMA Commission on New Minerals, Nomenclature and Classification. Canadian Mineralogist: 45: 983-1055; http://nrmima.nrm.se(2016) {{Cite Q, Q105611595, author=Stahle V., author2=Koch M., author3=McCammon C. A., author4=Mann U., author5=Markl G., author3-link=Catherine McCammon Taylor L. A. and PokhilenkoN., “Ferrous freudenbergite in ilmenite megacrysts: a unique paragenesis from the Dalnaya Kimberlite, Yakutia,” Am. Mineral. 82, 991– 1000 (1997). Yakovleva O. S. , “Mineral diversity of fenitized xenoliths in the Khibina Massif, Kola Peninsula,” in Mineral Diversity: Study and Conservation (Zemyata and Khorata, Sofia, 2009), pp. 193–199 n Russian Zaitsev, V. A., Kogarko, L. N. and Senin, V. G. (2013) ‘Phase equilibria in the system lamprophyllite-nepheline’, ''Geochemistry International'', 51(11), pp. 889–895.
Minerals