Čechit
| Čechit | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula |
|
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.BH.40 41.05.02.04 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 / m 2 / m 2 / m |
| Space group | Pnam (No. 62, position 6) |
| Lattice parameters | a = 7.61 Å ; b = 9.44 Å; c = 6.10 Å |
| Formula units | Z = 4 |
| Frequent crystal faces | {110}, {010} |
| Physical Properties | |
| Mohs hardness | 4.5 to 5 |
| Density (g / cm 3 ) | measured: 5.88; calculated: 5.94 |
| Cleavage | is missing |
| Break ; Tenacity | uneven to shell-like; brittle |
| colour | black |
| Line color | black |
| transparency | opaque (opaque) |
| shine | Resin gloss to semi-metallic gloss |
| magnetism | magnetic |
| Other properties | |
| Chemical behavior | easily soluble in HCl and HNO 3 (l: l) |
| Special features | magnetic |
Čechit is a very rarely occurring mineral from the mineral class of "phosphates, arsenates and vanadates" with the chemical composition Pb (Fe, Mn 2+ ) [OH | VO 4 ] and therefore chemically a lead - iron - vanadate with additional hydroxide ions . In the case of naturally formed cechites, however, part of the iron is usually replaced ( substituted ) by manganese , but always in the same proportion to the other components of the mineral.
Čechit crystallizes in the orthorhombic crystal system and develops mostly granular masses a few centimeters in size, consisting of black, rough and rounded crystals up to about three millimeters in length, which are stretched according to [001]. The mineral is opaque in every form and shows a resin-like to slightly metallic sheen on the surfaces of visible crystal surfaces .
Etymology and history
Čechit was discovered for the first time in the old spoil heaps of the "Alexander Mine" near Vrančice in Okres Příbram in the Czech Republic . It was first described in 1981 by Zdeněk Mrázek (1952–1984) and Zdeněk Táborský , who named the mineral after geochemist František Čech (1929–1995). From 1976 to 1990 he was head of the mineralogy department at the Charles University in Prague , which also stores type material of the mineral.
Despite the correct spelling of the mineral name with Hatschek in the first description in accordance with the specifications for mineral naming of the International Mineralogical Association (IMA), the newly recognized mineral was announced in the American Mineralogist in 1982 initially without Hatschek in the form Cechit (English Cechite ). The spelling of the name, which was also inconsistent in the specialist literature, was corrected with the publication “Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks” in 2008.
classification
Since the Čechit was only discovered in 1980 and recognized by the IMA as an independent mineral, it is not listed in the outdated 8th edition of the mineral classification according to Strunz . Only in the "Lapis mineral directory", which was last updated in 2018, which, out of consideration for private collectors and institutional collections, is still based on this classic system of Karl Hugo Strunz , the mineral received the system and mineral number. VII / B.27-40 . In the "Lapis system" this corresponds to the class of "phosphates, arsenates and vanadates" and there the section "Anhydrous phosphates, with foreign anions F, Cl, O, OH", where Čechit together with Arsendescloizit , Descloizit , Mottramit and Pyrobelonit the "Descloizit group" with the system no. VII / B.27 forms.
The 9th edition of Strunz's mineral systematics, valid since 2001 and updated by the International Mineralogical Association (IMA) until 2009, also assigns the Čechit to the section of “Phosphates etc. with additional anions; without H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of the other anions to the phosphate, arsenate or vanadate complex (RO 4 ), so that the mineral is classified in the sub-section “With medium-sized and mostly large cations; (OH etc.): RO 4 = 1: 1 “can be found, where together with Descloizit, Mottramit and Pyrobelonit the“ Descloizit group ”with the system no. 8.BH.40 forms.
Also the systematics of minerals according to Dana , which is mainly used in the English-speaking area , assigns the Čechit to the class of "phosphates, arsenates and vanadates", but there in the more finely divided division of "anhydrous phosphates, etc., with hydroxyl or halogen ". Here, however, he is also a member of the "Descloizit Group" with system no. 41.05.02 within the subsection of " Anhydrous phosphates etc., with hydroxyl or halogen with (AB) 2 (XO 4 ) Z q ".
Crystal structure
Čechit crystallizes orthorhombically in the space group Pnam (space group no. 62, position 6) with the lattice parameters a = 7.61 Å ; b = 9.44 Å and c = 6.10 Å and 4 formula units per unit cell .
properties
The mineral is easily soluble in hydrochloric acid (HCl) and nitric acid (HNO 3 ) (dilution 1: 1). In addition, Čechit shows magnetic properties.
Education and Locations
In its type locality , the old overburden dump of the "Alexander Pit" with Pb-Zn-Ag-Cu-U mineralization, Čechit occurred in paragenesis with calcite , hedyphane and hematite . So far the only other known location in the Czech Republic is also in Vrančice lying Pošepný- transition where the outcrop secondary minerals containing vanadium were found.
Other previously known sites are Isallo in the northern Italian municipality of Magliolo , the Maria Magdalena mine near Ulldemolins in the Catalan province of Tarragona in northeastern Spain and the “Silver Coin Mine” near Valmy in Humboldt County of Nevada in the USA.
See also
literature
- Z. Mrázek, Z. Táborský: Čechite, Pb (Fe + 2, Mn + 2) (VO4) (OH), a new mineral of the descloizite-pyrobelonite group . In: New yearbook for mineralogy, monthly books . 1981, p. 520-528 (English).
- Michael Fleischer , Louis J. Cabri, GY Chao, Joseph Anthony Mandarino , Adolf Pabst : New Mineral Names . In: American Mineralogist . tape 67 , 1982, pp. 1074-1082 ( minsocam.org [PDF; 1.1 MB ; accessed on May 30, 2019]).
Web links
- Mineral Atlas: Čechit (Wiki)
- Čechite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 30, 2019 .
- Čechite search results. In: rruff.info. Database of Raman spectroscopy, X-ray diffraction and chemistry of minerals (RRUFF), accessed on May 30, 2019 .
- American-Mineralogist-Crystal-Structure-Database - Cechite. In: rruff.geo.arizona.edu. Retrieved May 30, 2019 .
Individual evidence
- ↑ a b c Stefan Weiss: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
- ↑ a b Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: March 2019. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2019, accessed May 20, 2019 .
- ↑ a b c d e 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. 459 (English).
- ↑ David Barthelmy: Cechite MineralData. In: webmineral.com. Retrieved May 30, 2019 .
- ↑ a b c d e Čechite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 (English, handbookofmineralogy.org [PDF; 64 kB ; accessed on May 30, 2019]).
- ↑ a b c d e f g h Michael Fleischer , Louis J. Cabri, GY Chao, Joseph Anthony Mandarino , Adolf Pabst : New Mineral Names . In: American Mineralogist . tape 67 , 1982, pp. 1074-1082 ( minsocam.org [PDF; 1.1 MB ; accessed on May 30, 2019]).
- ^ Catalog of Type Mineral Specimens - Cechite. (PDF 130 kB) In: docs.wixstatic.com. Commission on Museums (IMA), December 12, 2018, accessed May 30, 2019 .
- ↑ 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 . tape 36 , 1998, pp. 8–9 (English, cnmnc.main.jp [PDF; 336 kB ; accessed on May 30, 2019]).
- ^ Ernst AJ Burke: Tidying up Mineral Names: an IMA-CNMNC Scheme for Suffixes, Hyphens and Diacritical marks . In: Mineralogical Record . tape 39 , no. 2 , 2008, p. 133 ( cnmnc.main.jp [PDF; 2.8 MB ; accessed on May 30, 2019]).
- ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed April 25, 2019 .
- ↑ Find location list for Čechit in the Mineralienatlas and in Mindat