Fluorapophyllite (Na)
| Fluorapophyllite (Na) | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula |
|
|
Mineral class (and possibly department) |
Silicates and germanates ( phyllosilicates ) |
|
System no. to Strunz and to Dana |
9.EA.15 ( 8th edition : VIII / H.01) 72.03.01.03 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 / m 2 / m 2 / m |
| Space group | Pnnm (No. 58) |
| Lattice parameters | a = 8.875 Å ; b = 8.881 Å; c = 15.79 Å |
| Formula units | Z = 2 |
| Frequent crystal faces | {100}, {010}, {001}, {111} |
| Physical Properties | |
| Mohs hardness | 4 to 5 |
| Density (g / cm 3 ) | 2.50 (measured, with inclusions!); 2.30 (calculated) |
| Cleavage | very perfect after {001}, bad after {110} |
| Break ; Tenacity | uneven; brittle [in each case by analogy to fluorapophyllite (K)] |
| colour | colorless to white, brownish yellow to yellowish brown |
| Line color | light gray |
| transparency | translucent to translucent |
| shine | Glass to mother-of-pearl gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.536 n β = 1.538 n γ = 1.544 |
| Birefringence | δ = 0.008 |
| Optical character | biaxial positive |
| Axis angle | 2V = 32 ° (measured), 2V = 62 ° (calculated) |
| Other properties | |
| Chemical behavior | Easily soluble in 1: 1 diluted HCl and 1: 1 diluted HNO 3 |
Fluorapophyllite- (Na) is a rarely occurring mineral from the group of apophyllites within the mineral class of " silicates and germanates ". It crystallizes in the orthorhombic crystal system with the chemical formula NaCa 4 [F | (Si 4 O 10 ) 2 ] · 8H 2 O, so from a chemical point of view it is a water-containing sodium - calcium - silicate with additional fluoride ions , which structurally corresponds to the layered silicates (phyllosilicates) heard.
Fluorapophyllite (Na) is the end member of the fluorapophyllite (Na) -fluorapophyllite (K) pseudo mixed crystal series , which bridges the change between orthorhombic and teragonal symmetry . The crystals at the type locality show a continuous and discontinuous zoning with edge areas of K-rich fluorapophyllite (K) and core areas of Na-rich fluorapophyllite (Na). At the type locality, fluorapophyllite (Na) and fluorapophyllite (K) can be visually differentiated from each other by different colors, but X-ray diffractometric and / or chemical analyzes are necessary for an exact assignment .
Fluorapophyllite- (Na) forms idiomorphic to subidiomorphic crystals up to 1 mm in size , which appear pseudotetragonal to pseudocubic due to the more or less balanced formation of the pinacoids {100}, {010} and {001} as well as the dipyramid {111}. They are either colorless to white or brownish yellow to yellowish brown. At the type locality they come in a kontaktmetamorphen magnetite - deposit in between granites and marbles occurring skarn before.
Etymology and history
Orthorhombic, generally fluorine-rich varieties of potassium-accentuated apophyllites were described as early as the 1960s. Although sodium in such potassium-accentuated apophyllites (now known as "fluorapophyllite- (K)") can substitute potassium to a certain extent, apophyllites in which the contents of sodium exceed those of potassium have only been used since the mid-1970s known. A team of Japanese-Canadian scientists led by geologist Professor Hiroharu Matsueda examined these apophyllites in detail and was able to determine that these sodium-rich phases are generally orthorhombic and fluorinated representatives of the apophyllites, and that a new mineral is therefore present. The mineral was recognized by the International Mineralogical Association (IMA) in October 1976 and described as natroapophyllite by Hiroharu Matsueda , Yasunori Miura, and John Rucklidge in 1981. It was named after the dominance of sodium over potassium and after its crystal-chemical relationship to other representatives of the apophyllite group. In 2008 Ernst Burke renamed the representatives of the apophyllite group, which turned natroapophyllite into "apophyllite (NaF)". This renaming was reversed in 2015 and the dominant monovalent cation was added to the mineral name as a suffix in brackets and the dominant non-tetrahedral anion was added to the mineral name as a prefix to delimit the individual species . The mineral name recognized by the IMA is now fluorapophyllite (Na).
Type material of the mineral is in the National Museum of Natural Sciences , Shinjuku near Tokyo , (Catalog No. M21067); at the Institute of Mining Geology at Akita International University , Akita , Japan ; and in the National Museum of Natural History , Washington, DC , USA (Catalog No. 136398).
classification
In the meanwhile outdated, but still in use 8th edition of the mineral systematics according to Strunz , fluorapophyllite (Na) belongs to the mineral class of "silicates and germanates" and there to the department of "phyllosilicates (phyllosilicates)", where together with fluorapophyllite (K) and hydroxyapophyllite- (K) the apophyllite group with the system no. VIII / H.01 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also assigns fluorapophyllite (Na) to the class of "silicates and germanates" and there in the department of "phyllosilicates" " a. This section is, however, further subdivided according to the structure of the layers, so that the mineral, according to its structure, can be found in the sub-section “Simple tetrahedral networks with 4, 5, (6) and 8 participating rings”, where it can be found together with fluorapophyllite (K ) and hydroxyapophyllite (K) the apophyllite group with the system no. 9.EA.15 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns fluorapophyllite (Na) to the class of "silicates and germanates" and there in the department of "layered silicate minerals". Here it is together with fluorapophyllite (K), hydroxyapophyllite (K) and carletonite in the " apophyllite group (4- and 8-membered rings) " with the system no. 72.03.01 within the sub-section " Layered silicates: two-dimensional, unlimited layers with rings other than six-membered: 3-, 4-, or 5-membered rings and 8-membered rings ".
Chemism
Fluorapophyllit- (Na) has (on basis of 8 silicon atoms per formula) the measured composition (Na 0.90 K 0.06 ) Σ = 0.96 Ca 4.13 Si 8 O 20.07 F 1.09 · 8.6H 2 O, which was idealized to NaCa 4 Si 8 O 20 F · 8H 2 O. The most sodium-rich sample from the type locality has a Na 2 O content of 3.05% by weight .
Formally and from a chemical point of view, fluorapophyllite- (Na) can be understood as the sodium-dominant analog of the potassium-dominated fluorapophyllite- (K). However, both do not form a continuous mixed crystal row , especially since it is also not known at which composition the change between orthorhombic and tetragonal symmetry occurs and whether there are miscibility gaps .
Crystal structure
Fluorapophyllite (Na) crystallizes in the orthorhombic crystal system in the space group Pnnm (space group no. 58) with the lattice parameters a = 8.875 Å , b = 8.881 Å and c = 15.79 Å as well as two formula units per unit cell .
The structure of fluorapophyllite- (Na) is made up of layers or networks of four-rings with corner-sharing [SiO 4 ] 4− tetrahedra, which alternately point up and down with respect to the c-axis. The layers between the tetrahedron layers contain the calcium and sodium atoms. Fluorapophyllite- (Na) is essentially isotypic or isostructural to fluorapophyllite- (K) and hydroxyapophyllite- (K), with potassium being substituted by sodium. The ion pairs Si, Ca, O (2), O (3), O (4) have two independent coordinate sets due to the lowering of the symmetry from tetragonal to orthorhombic. The tetrahedra around the two silicon atoms have slightly different configurations and form rings of four around the twofold axis. Figure-of-eight rings made of corner-sharing [SiO 4 ] 4− tetrahedra are also located in this plane, creating a layer structure parallel to the very perfect cleavage according to {001}. The calcium and sodium polyhedra in fluorapophyllite (Na) are significantly more distorted compared to the tetragonal representatives of the apophyllite group, which is due to the substitution of potassium by sodium.
properties
.png)
morphology
Fluorapophyllite- (Na) forms up to 2 mm large, idiomorphic to subidiomorphic crystals, which represent combinations of the pinacoids {100}, {010} and {001} as well as the orthorhombic dipyramid {111}. The faces of {111} are often striped perpendicular to the c-axis [001]. Since the surface forms mentioned are mostly in equilibrium, the crystals appear pseudo-tetragonal to almost pseudo-cubic. In all known cases, the crystals are composed in such a way that the inner area consists of fluorapophyllite (Na) and the edge area of the crystals consists of fluorapophyllite (K). This is also the reason why the external morphology of the composite crystals is similar to that of fluorapophyllite- (K).
physical and chemical properties
Fluorapophyllite- (Na) is either colorless to white or brownish-yellow to yellowish-brown, the color of the streak of the mineral, however, is always light gray. The surfaces of the translucent to transparent crystals have a glass-like to mother-of-pearl-like sheen .
Fluorapophyllite (Na) is colorless in the thin section. As an orthorhombic mineral, its otic character is biaxially positive; the axis angle 2V is 32 ° (measured) or 62 ° (calculated).
Fluorapophyllite- (Na) shows a very perfect cleavage according to {001} and a second, clearly poorer cleavage according to {110}. With a Mohs hardness of 4 to 5, fluorapophyllite (Na) is one of the medium-hard minerals that, like the reference minerals fluorite and apatite, can be scratched more or less easily with a pocket knife. The measured density for fluorapophyllite (Na) is 2.50 g / cm³, the calculated density is 2.30 g / cm³. The differences can be attributed to the fact that the fluorapophyllite (Na) inclusions of the significantly heavier minerals calcite and fluorite are present.
The mineral is easily soluble in 1: 1 diluted hydrochloric acid and 1: 1 diluted nitric acid.
Modifications and varieties
Fluorapophyllite (Na) crystals from the type locality and from many other localities are zoned continuously or discontinuously. They always have a core made of fluorapophyllite- (Na) on which a more or less thin border of fluorapophyllite- (K) has grown. In the Fengjiashan mine, the core of the “apophyllite” crystals consists of fluorapophyllite (Na) with (Na 0.8 K 0.2 ) and the edge area of formula-pure fluorapophyllite (K) with (K 1.0 ). Investigations into whether all apopophyllites in this deposit are zoned intergrowths of fluorapophyllite (Na) and fluorapophyllite (K) are missing.
Education and Locations
Among the around 1100 sites known for “apophyllite” worldwide so far (as of 2016), there are only around 10 locations in which the mineral fluorapophyllite (Na) has been identified. The type locality of the fluorapophyllite (Na) is the "Sampo Mine" (Shitouyouze, Bicchu-cho), which is a few tens of kilometers west of the city of Takahashi in Okayama prefecture within the Chūgoku region on Honshū in Japan .
On the type locality of Fluorapophyllit- (Na) is used in a kontaktmetamorphen or kontaktmetasomatischen magnetite - deposit before occurring in between granites and marbles skarns. The deposit was created at the contact of Paleozoic limestone and slate with a late Cretaceous granite. The mineral occurred here on the 9th floor of the pit, in the "White Skarn" within ore body No. I Yoshiki, close to the contact with the marble. Accompanying minerals are zeophyllite , cuspidin , fluorapophyllite (K) and calcite as well as andradite , xonotlite , fluorite, wollastonite , a clinopyroxene of the diopside - hedenbergite series, magnetite, quartz and solid bismuth . The fluorine-containing silicates zeophyllite and apophyllite crystallized during a hydrothermal alteration stage that took place after the thermometamorphism and the formation of skarns caused by granite intrusion. The white skarn was formed by fluorometasomatosis from ferrobustamite and wollastonite-andradite skarns.
Other sites include several locations in the United States in North America. Fluorapophyllite (Na) is known there from the “Goldstrike Mine”, Lynn District, Eureka County , Nevada , in the form of clear pseudocubic crystals up to 2 mm in size from veins that set through a calcareous silicate rock. Also from the "Getchell Mine" on Adam Peak in the Potosi District, Osgood Mts., Humboldt Co. , Nevada, from a drill core. In addition, from the "Palmer Shaft" of the Franklin Mine near Franklin in the mining district of the same name, Sussex County , New Jersey , and from the "Valley Landfill Pit" (S2F Quarry) near Coffin Butte in Benton Co. , Oregon . From the "Black Rock" location near Morden on the Bay of Fundy , Kings Co. , Nova Scotia , Canada , together with quartz.
From the "Fengjiashan Mine" (Daye Copper Mine), Daye , district-free city of Huangshi , Hubei Province , China , in zoned crystals with Hubeit , Inesite , quartz, pyrite and calcite. The colorless, always thin or thick tabular crystals reach edge lengths of up to 10 cm.
From Macquarie (Macquarie Iceland) in Tasmania , Australia .
In Europe from a Amazonit - pegmatite at Laitila in the landscape Finland Proper , Finland , and the "Boghill Quarry" at Glengormley in the district of Antrim and Newtownabbey , Northern Ireland , United Kingdom . Find places in Germany , Austria and Switzerland are unknown.
See also
literature
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Enke , Stuttgart 1978, ISBN 3-432-82986-8 , pp. 739-740 (first edition: 1891).
- Martin Okrusch , Siegfried Matthes : Mineralogy: An introduction to special mineralogy, petrology and deposit science . 8th edition. Springer, Berlin Heidelberg 2009, ISBN 978-3-540-78200-1 , p. 154-155 (first edition: 1983).
- William Alexander Deer , Robert Andrew Howie , Jack Zussman : Rock-forming minerals Vol. 3B: Layered silicates excluding micas and clay minerals . 2nd Edition. Geological Society, London 2009, ISBN 978-1-86239-259-5 , pp. 288-304 (first edition: 1961).
- Helmut Schrätze, Karl-Ludwig Weiner: Mineralogy. A textbook on a systematic basis . de Gruyter, Berlin; New York 1981, ISBN 3-11-006823-0 , pp. 803-804 (apophyllite).
- Natroapophyllite [Fluorapophyllite- (Na)], In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF, 70 kB )
Web links
- Mineral Atlas: Apophyllite (NaF) (Wiki)
- Webmineral - Apophyllite- (NaF)
- Mindat - Fluorapophyllite- (Na)
- IMA / CNMNC List of Mineral Names; May 2016 (English, PDF 1.6 MB)
- American-Mineralogist-Crystal-Structure-Database - List of structural analyzes of the various apophyllite individual minerals
Individual evidence
- ^ A b Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 659 .
- ↑ a b c d Natroapophyllite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF, 76 kB )
- ↑ a b c d e f g h i j k l m n o p Hiroharu Matsueda, Yasunori Miura, John Rucklidge: Natroapophyllite, a new orthorhombic sodium analog of apophyllite - I. Description, occurrence, and nomenclature . In: The American Mineralogist . tape 66 , 1981, pp. 410-415 ( rruff.info [PDF; 1.4 MB ]).
- ↑ Thure Georg Sahama : Yellow apophyllite from Korsnäs, Finland . In: Mineralogical Magazine . tape 34 , 1965, pp. 406-415 ( rruff.info [PDF; 1.3 MB ]).
- ↑ MR Belsare: A chemical study of apophyllites from Poona . In: Mineralogical Magazine . tape 37 , 1969, p. 288–289 ( rruff.info [PDF; 115 kB ]).
- ↑ Hiroharu Matsueda: "Na-apophyllite" from the skarn of the Sampo Mine, Okayama Prefecture, Japan (abstract, in Japanese) . In: Annual Joint Meeting of Japanese Association of Mineralogists, Petrologists, and Economic Geologists; Mineralogical Society of Japan; and Mining Geology. Abstracts with Program (Kofu) . tape 1975 , 1975, p. 75 .
- ↑ Ernest AJ Burke: Tidying up mineral names: an IMA-CNMNC scheme for suffixes, hyphens and diacritical marks . In: The Mineralogical Record . tape 39 , 2008, p. 131-135 .
- ↑ Frédéric Hatert, Stuart J. Mills, Marco Pasero, Peter A. Williams: CNMNC guidelines for the use of suffixes and prefixes in mineral nomenclature, and for the preservation of historical names . In: European Journal of Mineralogy . tape 25 , 2013, p. 113–115 , doi : 10.1127 / 0935-1221 / 2013 / 0025-2267 ( eurjmin.geoscienceworld.org [PDF; 46 kB ]).
- ^ IMA / CNMNC List of Mineral Names; May 2016 (PDF; 1.6 MB)
- ↑ Yasunori Miura, Toshio Kato, John Rucklidge, Hiroharu Matsueda: Natroapophyllite, a new orthorhombic sodium analog of apophyllite - II. Crystal structure . In: The American Mineralogist . tape 66 , 1981, pp. 416-423 ( rruff.info [PDF; 1.4 MB ]).
- ^ A b Frank C. Hawthorne, Mark A. Cooper, Joel D. Grice, Andrew C. Roberts, William R. Cook Jr., Robert Lauf: Hubeite, a new mineral from the Daye mine near Huangshi, Hubei Province, China . In: The Mineralogical Record . tape 33 , 2002, pp. 455-471 .
- ↑ a b Berthold Ottens : China: Minerals - Locations - Deposits . 1st edition. Christian Weise Verlag, Munich 2008, ISBN 978-3-921656-74-7 , p. 182, 471 .
- ↑ Mindat - Number of localities for the apophyllite group
- ↑ Mindat - Number of localities for fluorapophyllite (Na)
- ↑ a b List of locations for fluorapophyllite (Na) in the Mineralienatlas and Mindat
- ↑ Mindat - type locality for fluorapophyllite (Na)
- ↑ a b Stephen B. Castor, Gregory C. Ferdock: Minerals of Nevada (Nevada Bureau of Mines and Geology Special Publication 31) . 1st edition. Nevada Bureau of Mines and Geology and University of Nevada Press, Reno & Las Vegas 1978, ISBN 0-87417-540-2 , pp. 344 .
- ^ Georgia Pe-Piper: Mode of occurrence, chemical variation and genesis of mordenite and associated zeolites from the Morden area, Nova Scotia, Canada . In: The Canadian Mineralogist . tape 38 , 2000, pp. 1215–1232 , doi : 10.2113 / gscanmin.38.5.1215 .