Béhierit

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Béhierit
Behierite-70408.jpg
Béhierite from the Antsongombato gem mine, Andrembesoa municipality, Vakinankaratra , Madagascar (size: 3.8 cm × 3.3 cm × 2.6 cm)
General and classification
other names
  • Behiérit
  • Behierit
  • IMA 15-E
chemical formula
  • Ta (BO 4 )
  • (Ta, Nb) [BO 4 ]
Mineral class
(and possibly department) 		Borates (formerly carbonates, nitrates and borates)
System no. to Strunz
and to Dana 		6.AC.15 ( 8th edition : V / G.07)
01/24/10/01
Crystallographic Data
Crystal system tetragonal
Crystal class ; symbol ditetragonal-dipyramidal; 4 / m  2 / m  2 / m
Space group I 4 1 / amd (No. 141)Template: room group / 141
Lattice parameters a  = 6.21  Å ; c  = 5.48 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 7 to 7.5
Density (g / cm 3 ) measured: 7.86 (5); calculated: 7.91
Cleavage clearly after {110} and {010}
Break ; Tenacity slightly mussel-like
colour gray pink
Line color White
transparency translucent
shine Diamond luster
Crystal optics
Refractive indices n ω  > 2
n ε  > 2
Optical character uniaxial positive

Béhierite (formerly Behierite ) is a very rare mineral from the mineral class of " borates " with the idealized chemical composition Ta (BO 4 ) and is therefore chemically a tantalum borate.

Béhierite crystallizes in the tetragonal crystal system and develops pseudo- octahedral crystals up to about seven millimeters in size. As a tantalum analogue of the mineral schiavinatoite (Nb [BO 4 ]), behierite can occur in aggregates with this mineral . However, due to the chemical similarity of the two elements, part of the tantalum is usually replaced ( substituted ) by niobium in the case of naturally formed behierites . Therefore, the chemical composition is often given in various sources as a mixed formula with (Ta, Nb) [BO 4 ]. The elements indicated in the round brackets can represent each other in the formula, but are always in the same proportion to the borate content of the mineral.

The mineral is translucent and has a diamond-like sheen on the surfaces of the gray-pink crystals . However, its streak color is white. With a Mohs hardness of 7 to 7.5, Béhierite is one of the hard minerals and, like the reference mineral quartz (hardness 7), is able to scratch window glass.

Etymology and history

Béhierite was first discovered in the pegmatites of Manjaka (Ampakita; Sahananana) in the Sahatany Valley in the Antsirabe II district of the Vakinankaratra ( Vàkinankàratra ) region on the island republic of Madagascar . The mineral was first analyzed and described in 1961 by ME Mrose and HJ Rose, who named it after the French mineralogist Jean Béhier (1903-1965).

In the first description as well as in older publications, the mineral name can be found in the spelling Behierite (without acute above the first e), which, however, does not correspond to the specifications for mineral naming of the IMA, after which, for example, minerals that were named after a person are on it It must be ensured that the spelling of the name is adopted (the only exceptions are spaces and capital letters, which are removed from the mineral name). One exception, with the correct spelling of Béhierit, is the publication of the 16th edition of Klockmann's textbook on mineralogy in 1978 .

The inconsistent spelling of their names in many minerals was corrected with the publication Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks in 2008 and in 2015 in Newsletter 28 of the IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) made up for some missing mineral names such as Béhierite. Since then, Béhierit has been used internationally in the spelling with the associated acute.

The type material of the mineral is in the National Museum of Natural History in Washington, DC (USA) under the catalog no. 139602 kept.

classification

In the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the behierite belonged to the common mineral class of "carbonates, nitrates and borates" and there to the department of "island borates", where together with Sinhalite it forms the "Sinhalite-Béhierite group" “With the system no. V / G.08 and the other members Pseudosinhalit and Schiavinatoit .

The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns Béhierite to the newly defined class of "borates" and there into the department of "monoborates". This is further subdivided according to the structure of the borate complex, the possible presence of further anions and the number of certain borate building groups, so that the mineral according to its structure in the subdivision “B (O, OH) 4 , with and without additional anions; 1 ( T ), 1 (T) + OH etc. ”can be found, where only together with Schiavinatoit the“ Béhierite group ”with the system no. 6.AC.15 forms.

The systematics of minerals according to Dana , which is predominantly used in the English-speaking world , assigns the Béhierite to the common class of "carbonates, nitrates and borates" and there in the department of " phosphates ", like the outdated Strunz system . Here he can also be found together with Schiavinatoit in the unnamed group 01/24/02 within the subdivision “ 01/24 Anhydrous borates with (A) 2+ XO 4 ”.

Chemism

The electron beam microanalysis of mineral samples from the Antsongombato mine in the municipality of Andrembesoa in the Betafo district bordering the type locality revealed an average composition of [15.77]% B 2 O 3 (calculated from stoichiometry), 63.95% Ta 2 O 5 and 21.73% Nb 2 O 5 . The empirical formula derived from the results is given as (Ta 0.64 Nb 0.36 ) Σ = 1.00 BO 4 .

In comparison, the synthetic compound (Ta, Nb) BO 4 with the molar ratio Ta: Nb = 1: 1 consists of 16.44% B 2 O 3 , 52.18% Ta 2 O 5 and 31.38% Nb 2 O 5 .

Crystal structure

Béhierite crystallizes tetragonally in the space group I 4 1 / amd (space group no. 141) with the lattice parameters a  = 6.21  Å and c  = 5.48 Å and 4 formula units per unit cell . Template: room group / 141

The crystal structure corresponds to that of zircon .

Education and Locations

Béhierite forms in granitic pegmatites . At its type locality Manjaka in the Sahatany Valley (Antsirabe II district), albite , manganese-containing apatite , elbaite , lepidolite , pollucite and quartz were found as accompanying minerals . In the above-mentioned Antsongombato mine (also in the Vakinankaratra region of Madagascar), feldspar , liddicoatite , rhodizite and schiavinatoite were added.

In addition to the sites already mentioned, the mineral is known so far (as of 2018) only from the Antandrokomby pegmatites in the Manandona valley ( Ambositra district ) in the Amoron'i Mania region on Madagascar and from the "Animikie Red Ace" - and the " Pine River ”pegmatites near Fern in Florence County , Wisconsin.

See also

literature

  • J. Behier: Travaux mineralogiques, Republique Malgache . In: Report Annuel du Service Geologique . 1960, p. 181–199 ( rruff.info [PDF; 1.4 MB ; accessed on June 16, 2018]).
  • ME Mrose, HJ Rose: Behierite, (Ta, Nb) BO4, a new mineral from Manjaka, Madagascar . In: Geological Society of America, Abstracts Annual Meetings . 1961, p. 111A-111A .
  • Michael Fleischer : New mineral names . In: American Mineralogist . tape 46 , 1961, pp. 765-770 ( rruff.info [PDF; 383 kB ; accessed on June 16, 2018]).
  • Michael Fleischer : New mineral names . In: American Mineralogist . tape 47 , 1962, pp. 414-420 ( rruff.info [PDF; 502 kB ; accessed on June 16, 2018]).
  • Commission on new minerals and mineral names . In: International Mineralogical Association (Ed.): Mineralogical Magazine . tape 36 , 1967, p. 131–136 ( rruff.info [PDF; 205 kB ; accessed on June 16, 2018]).
  • Klaus-Jürgen Range, Manfred Wildenauer, Anton Michal Heyns: Extremely short, non-binding oxygen-oxygen distances: The crystal structures of NbBO 4 , NaNb 3 O 8 and NaTa 3 O 8 . In: Angewandte Chemie . tape 100 , no. 7 , July 1988, p. 973-975 , doi : 10.1002 / anie.19881000721 .
  • U. Hålenius, F. Hatert, M. Pasero, SJ Mills: IMA Commission on New Minerals, Nomenclature and Classification (CNMNC): Newsletter 28. New minerals and nomenclature modifications approved in 2015 . In: Mineralogical Magazine . tape 79 , 2015, p. 1859–1864 ( rruff.info [PDF; 81 kB ; accessed on June 16, 2018]).

Web links

Commons : Béhierite  - collection of images, videos and audio files

Individual evidence

  1. ↑ Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p.  732 .
  2. ↑ a b U. Hålenius, F. Hatert, M. Pasero, SJ Mills: IMA Commission on New Minerals, Nomenclature and Classification (CNMNC): Newsletter 28. New minerals and nomenclature modifications approved in 2015 . In: Mineralogical Magazine . tape 79 , 2015, p. 1864 ( rruff.info [PDF; 81 kB ; accessed on June 16, 2018]).
  3. ↑ a b c IMA / CNMNC List of Mineral Names; March 2018 (PDF 1.65 MB)
  4. ↑ a b c d e f Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  335 .
  5. ↑ Webmineral - Béhierite (English)
  6. ↑ a b c d e f g h Béhierite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 63  kB ; accessed on June 16, 2018]).
  7. ↑ a b Mindat - Béhierite (English)
  8. ^ Ernest H. Nickel , Joel D. Grice: The IMA Commission on New Minerals and Minerala Names: Procedures and Guidelines on Mineral Nomenclature , In: The Canadian Mineralogist , Volume 36 (1998); PDF 328 kB , from p. 8
  9. ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp.  586 (first edition: 1891).
  10. ^ Ernst AJ Burke: Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks , In: Mineralogical Record , Volume 39, No. 2 (March – April 2008); PDF 2.7 MB
  11. ↑ Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason , Abraham Rosenzweig: Dana's New Mineralogy . 8th edition. John Wiley & Sons, New York (et al.) 1997, ISBN 0-471-19310-0 , pp. 534 .
  12. ↑ Find location list for Béhierite at the Mineralienatlas and at Mindat