Nickenichit
| Nickenichit | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1992-014 |
| chemical formula |
|
|
Mineral class (and possibly department) |
Phosphates, arsenates and vanadates |
|
System no. to Strunz and to Dana |
8.AC.10 ( 8th edition : VII / A.07) 02.38.03.09 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic; 2 / m |
| Space group | C 2 / c (No. 15) |
| Lattice parameters |
a = 11.882 Å ; b = 12.760 Å; c = 6.647 Å β = 112.81 ° |
| Formula units | Z = 4 |
| Frequent crystal faces | {010}, {100} and {10 1 } |
| Physical Properties | |
| Mohs hardness | ≈ 3 |
| Density (g / cm 3 ) | 4.06 (calculated) |
| Cleavage | excellent according to {010}, good according to {100} and {10 1 } |
| Break ; Tenacity | not specified; brittle |
| colour | light blue, gray blue |
| Line color | not specified, probably very light blue |
| transparency | translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.714 (5) n β = 1.744 (5) n γ = 1.783 (5) |
| Birefringence | δ = 0.069 |
| Optical character | biaxial positive |
| Axis angle | 2V = 60 (6) ° (measured), 84 ° (calculated from the refractive indices) |
| Pleochroism | clearly from light blue to blue |
Nickenichite is a very seldom occurring mineral from the mineral class of " phosphates , arsenates , and vanadates " with the chemical formula (Na, Ca, Cu) 1.6 (Mg, Fe 3+ ) 3 [AsO 4 ] 3 . From a chemical point of view, the mineral is therefore a sodium - magnesium - arsenate .
Nickenichite crystallizes in the monoclinic crystal system and develops up to 0.2 mm long, fibrous to prismatic, elongated according to [10 1 ] crystals , which form radial or parallel {010} lamellar aggregates .
Etymology and history
As discoverer of Nickenichits the mineral collector Norbert Ballak from true Lonnig , Eifel , of the mineral in the continuation of an end of 1989 discovered tubular, approximately 0.5 m in diameter have fumarole into the slag degrading the Nickenicher saddle (Eicher saddle) at Nickenich close Andernach , Eifel, Rhineland-Palatinate , Germany , and provided the research material for the type publication. The mineral was examined by an Austrian-German research team led by M. Auernhammer , Herta Effenberger , Gerhard Hentschel , Thomas Reinecke and Ekkehard Tillmanns . After it was recognized by the International Mineralogical Association (IMA) in 1992, the official first description followed a year later in 1993. The authors named the mineral of its type locality, the slag mining on the Nickenicher saddle.
The holotype stage is in the collection of the Institute for Mineralogy and Crystallography of the University of Vienna , Austria .
classification
Already in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the nickenichite belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the division of "anhydrous phosphates [PO 4 ] 3− , without foreign anions", where he formed the unnamed group VII / A.07 together with Bradaczeckit , Johillerit , O'Danielit (Odanielit) and Yazganit .
The 9th edition of Strunz's mineral systematics , which has been valid since 2001 and is used by the IMA, also assigns nickenichite to the class of "phosphates, arsenates and vanadates" and there to the category of "phosphates, etc. without additional anions; without H 2 O “. However, this section is even more precisely subdivided according to the size of the cations involved , so that the mineral can be found according to its composition with the cations sodium and magnesium in the sub-section “With medium-sized and large cations”, where it can be found together with Alluaudit , Arseniopleit , Bradaczekit , Groatit (IMA 2008-054), Karyinit , Ferroalluaudit , Ferrohagendorfit , Hagendorfit , Johillerit, Maghagendorfit , Manitobait (IMA 2008-064), O'Danielit, Varulith and Yazganit the Hagendorfitgruppe with the system number. 8.AC.10 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns nickenichite to the class of "phosphates, arsenates and vanadates". Here he is in the " Alluaudit subgroup within the Alluaudit-Wyllieit group " with the system no. 38.02.03 and the other members Ferrohagendorfit, Hagendorfit, Varulith, Maghagendorfit, Ferroalluaudit, Alluaudit, O'Danielit, Johillerit, Yazganit, Groatit and Manitobait within the subdivision " Anhydrous phosphates etc., (A + B 2+ ) 3 (XO 4 ) 2 ”.
Crystal structure
Nickenichite crystallizes in the monoclinic crystal system in the space group C 2 / c (space group no. 15) with the lattice parameters a = 11.882 Å ; b = 12.760 Å; c = 6.647 Å and β = 112.81 ° as well as four formula units per unit cell .
Nickenichite shows close structural relationships with the minerals O'Danielite and Johillerite without actually being isotypic (isostructural) to them. The two crystallographically different octahedrally coordinated cation positions Me = (Mg, Fe, Al) have mean Me –O distances of 2.108 Å and 2.056 Å, the octahedra are linked via edges to form zigzag-like chains in [10 1 ], these be with each other via AsO 4 - tetrahedra linked. Furthermore, the compound is characterized by partially occupied Na [4 + 4] , Ca [6 + 2] and Cu [4] positions.
Chemism
Nickenichit has the measured chemical composition (Na 0.81 K 0.01 ) Σ = 0.82 Ca 0.27 Cu 0.32 (Mg 2.42 Fe 0.38 Al 0.12 Mn 0.03 ) Σ = 2 , 95 [(As 1.02 P 0.02 ) Σ = 1.04 O 4 ] 3 . According to the crystal structure determination, this results in Na 0.76 Ca 0.41 Cu 0.39 (Mg 2.33 Fe 0.52 Al 0.12 Mn 0.03 ) Σ = 3.00 [(As 0.98 P 0, 02 ) Σ = 1.00 O 4 ] 3 . From the chemical point of view, nickenichite can be distinguished from O'Danielite or Johillerite by the absence of zinc , the incorporation of trivalent cations and the incorporation of calcium atoms in a structural position that is not occupied at all in the two minerals mentioned.
properties
morphology
Nickenichite forms fibrous or prismatic crystals up to 0.2 mm long, elongated according to [10 1 ] , which usually come together to form radial - less often also parallel {010} lamellar - aggregates that grew flat on the cavity walls. The diameter of the individual crystals is rarely greater than 0.03 mm. The surface shapes {010}, {100} and {10 1 } have been identified on the crystals . Only in rare cases are fibrous to fine-needle nickenichite crystals grown together in three dimensions to form hedgehog-like aggregates.
physical and chemical properties
The crystals of the nickenichite are light blue to gray-blue, while the line color of the mineral is not specified. It is very likely that the color of the mineral powder will be a very light blue. The crystals from the second locality Nickenicher Weinberg show a purple-tinged, dark blue. The translucent crystals have a glass-like sheen , which is also reflected in the comparatively low light refraction of 1.714 to 1.744 and the birefringence of 0.069. The mineral has three different levels of cleavage . It splits excellently after {010} and well after {100} and {10 1 }. With a Mohs hardness of approx. 3, nickenichite is one of the medium-hard minerals and, if the crystals are sufficiently large, it could be scratched by a copper coin like the reference mineral calcite . The calculated density is 4.06 g / cm³.
Education and Locations
Nickenichite is a very rare mineral formation and is known so far (as of 2016) from only two sites. The type of locality is the slag pit at the "Nickenicher Sattel" near Nickenich not far from Andernach in the Eifel, Rhineland-Palatinate. The second site is the basalt lava quarry at the "Nickenicher Weinberg" (Nickenicher Sattelberg) near Nickenich, not far from the type locality, 6 km southwest of Andernach. Material with nickenichite was recovered from the type locality a few years after the find - but the nickenichite was not clearly identified until 1999. Locations in Austria and Switzerland are unknown.
When it was first found, it was the roof area of a larger cavity between two fumarole canals, which has since become known as the nickenichite-containing fumarole . The roof area and the two fumarole channels were coated with striking, unusually colorful minerals for an occurrence in basalt cinder. The nickenichite was only found in a narrowly limited area between the fumaroles. Like his companions, he represents an education that has been deposited from hot fumarole gases. Whitish vanadinite crystals and yellow-green to yellow, powdery duhamelite have been identified as accompanying minerals to nickenite , whereby the latter turned out to be Ca- and Bi-containing mottramite and was discredited as a separate mineral in 2003. Calcite , cerussite , malachite and chrysocolla were found in the wider area . At the Nickenich vineyard, nickenichite covers the fumarole walls together with kidney yellow, often powdery mottramite crusts. In some cases, nickenichite is also speckled or covered in pustules with yellow mottramite.
See also
literature
- M. Auernhammer, Herta Effenberger, Gerhard Hentschel, Thomas Reinecke, Ekkehard Tillmanns: Nickenichite, a new Arsenate from the Eifel, Germany . In: Mineralogy and Petrology . tape 48 , 1993, pp. 153-166 .
- Nickenichite . 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; 432 kB ]).
Web links
- Mineral Atlas: Nickenichite (Wiki)
- Webmineral - Nickenichite
- Mindat - Nickenichite
- American-Mineralogist-Crystal-Structure-Database - Nickenichite
Individual evidence
- ^ A b 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. 430 .
- ↑ a b c d e Nickenichite . 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; 432 kB ]).
- ↑ a b c d Mindat - Nickenichite
- ↑ a b c d e f g h i j k l m n o p M. Auernhammer, Herta Effenberger, Gerhard Hentschel, Thomas Reinecke, Ekkehard Tillmanns: Nickenichite, a new Arsenate from the Eifel, Germany . In: Mineralogy and Petrology . tape 48 , 1993, pp. 153-166 .
- ^ Gerhard Hentschel: New minerals from the Eifel: Bellbergite, Nickenichit and Orschallit . In: Lapis . tape 19 , no. 3 , 1994, p. 20-22 .
- ^ A b Hans Egon Künzel, Günter Blaß, Willi Schüller: Minerals - Bombs - Grotto stones: The Nickenich vineyard . In: Lapis . tape 36 , no. 7/8 , 2011, pp. 55-66 .
- ↑ Mindat - Number of localities for Nickenichit
- ↑ Find location list for nickenichite at the Mineralienatlas and at Mindat