Zeophyllite
| Zeophyllite | |
|---|---|
 |
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| General and classification | |
| other names |
|
| chemical formula |
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Mineral class (and possibly department) |
Silicates and germanates - layered silicates |
|
System no. to Strunz and to Dana |
9.EE.70 ( 8th edition : VIII / E.14) January 73, April 01 |
| Crystallographic Data | |
| Crystal system | trigonal |
| Crystal class ; symbol | trigonal-rhombohedral; 3 |
| Space group | R 3 (No. 148) |
| Lattice parameters | a = 9.38 Å ; c = 36.57 Å |
| Formula units | Z = 3 |
| Physical Properties | |
| Mohs hardness | 3 |
| Density (g / cm 3 ) | measured: 2.747 to 2.764; calculated: [2.75] |
| Cleavage | completely after {0001} |
| colour | colorless, white |
| Line color | White |
| transparency | translucent |
| shine | Glass gloss, pearlescent |
| Crystal optics | |
| Refractive indices |
n ω = 1.565 to 1.577 n ε = 1.560 to 1.569 |
| Birefringence | δ = 0.005 to 0.008 |
| Optical character | uniaxial negative |
| Axis angle | 2V = 0 to 10 ° |
Zeophyllite is a rarely occurring mineral from the mineral class of " silicates and germanates ". It crystallizes in the trigonal crystal system with the chemical composition Ca 13 Si 10 O 28 (OH) 2 F 8 · 6H 2 O and chemical point of a water-containing , basic calcium - fluoro silicate. Structurally, it belongs to the layered silicates .
Zeophyllite is usually colorless and transparent, but can also appear white due to lattice defects or polycrystalline formation. It is mostly found in the form of hemispherical to spherical mineral aggregates of radial-rayed crystal flakes with a glass-like sheen on the surfaces (with thicker layers also pearlescent), which either grow on rock surfaces or, for example, natrolite stalks grow around them.
Etymology and history
Zeophyllite was first discovered in 1899 by a mineral trader named Leitenberger in a zeolite deposit near Velké Březno (German Großpriesen ) in Northern Bohemia, Czech Republic.
It was scientifically described in 1902 by Anton Pelikan (1861-1918), who, contrary to the term used by mineral dealers, Comptonite (actually Thomsonite ) after the Greek words ζέω [zeo] for swell or swell and ancient Greek φύλλον [phýllon] for leaf named. He wanted to record the two characteristic properties of the mineral: Its crystal forms, which predominantly appear in the leafy habitus, and its property of bulging or swelling when heated.
classification
Already in the outdated 8th edition of the mineral classification by Strunz of Zeophyllit belonged to the department of " phyllosilicates (phyllosilicates)" where he collaborated with Reyerit the "Reyerit-Zeophyllit group" with the system no. VIII / E.14 and the other members Fedorit and Gyrolith .
In the Lapis mineral directory according to Stefan Weiß, which, out of consideration for private collectors and institutional collections, is still based on this old form of Karl Hugo Strunz's system , the mineral was given the system and mineral number. VIII / H.34-50 . In the "Lapis Classification" This also corresponds department "phyllosilicates" where Zeophyllit with Armstrongit , Cairncrossit , Ellingsenit , fedorite, Gyrolith, Lalondeit , Martinit , Minehillit , Orlymanit , Reyerit, Truscottite and Tungusit an independent but unnamed group forms ( Status 2018).
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and was updated by the International Mineralogical Association (IMA) until 2009, also classifies zeophyllite in the “phyllosilicates” department. This is, however, further subdivided according to the layer structure, so that the mineral, according to its structure, can be found in the sub-section "Simple tetrahedral networks of 6-membered rings, connected by octahedral networks or bands", where it is the only member of the unnamed group 9. EE.70 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , also assigns the zeophyllite to the class of "silicates and Germanates", but there in the more finely subdivided division of "layered silicates with condensed tetrahedral layers". Here he is to be found as the only member in the unnamed group 73.01.04 within the sub-section “ Layered Silicates: Condensed Tetrahedral Layers with Double Layers ”.
Crystal structure
Zeophyllite crystallizes trigonal in the space group R 3 (space group no. 148) with the lattice parameters a = 9.38 Å and c = 36.57 Å as well as 3 formula units per unit cell .
Education and Locations
Zeophyllite forms secondarily through hydrothermal weathering in basalt bubbles . The accompanying minerals include apophyllite and calcite as well as natrolite, phillipsite and other zeolites.
As a rare mineral formation, zeophyllite could only be detected at a few sites, with around 20 sites being documented so far (as of 2020). In addition to its type locality Velké Březno ( Großpriesen ), the mineral could also be found in the Czech Republic on Starý vrch ( Altenberg ) near Radejčín in the municipality of Řehlovice and at Soutěsky in the same region of Ústí . Radejčín is also known as an important site for well-formed, spherical aggregates up to one centimeter in diameter.
In Germany, zeophyllite was found in the Weilberg quarry in North Rhine-Westphalia as well as in the Caspar quarry at Ettringer Bellerberg near Ettringen in the Eifel, in the "Ölberg" quarry near Hundsangen in the Westerwaldkreis and at the Schellkopf near Brenk in the Ahrweiler district in Rhineland-Palatinate.
The only known site in Austria so far is the Steinberg near Mühldorf near Feldbach in Styria.
Other well-known sites include the Monte Somma (Pollena-Trocchia) in Italy, the "Sampo" mine near Takahashi and Kōriyama on the Japanese island of Honshū, the Poudrette quarry on Mont Saint-Hilaire in Canada, Jolotca in the Romanian district of Harghita , the Mountain Lakargi in the Russian republic of Kabardino-Balkaria as well as the Kukiswumtschorr and the Hackmantal in the Chibinen on the Russian peninsula Kola, Ynglingarum in the southern Swedish province of Skåne län , the Láz near Uzsa in the Hungarian small area Tapolca and the "Marble Canyon Mine" in Culberson County in the US state of Texas.
See also
literature
- A. Pelikan: Contributions to the knowledge of the zeolites of Bohemia . In: Meeting reports of the Academy of Sciences in Vienna, mathematical and natural science class . tape 111 , 1902, pp. 334–347 ( rruff.info [PDF; 1.4 MB ; accessed on March 7, 2020]).
Web links
- Mineral Atlas: Zeophyllite (Wiki)
- Zeophyllite search results. In: rruff.info. Database of Raman spectroscopy, X-ray diffraction and chemistry of minerals (RRUFF), accessed March 7, 2020 .
Individual evidence
- ^ Friedrich Klockmann : Klockmanns textbook of mineralogy . Ed .: Paul Ramdohr , Hugo Strunz . 16th edition. Enke, Stuttgart 1978, ISBN 3-432-82986-8 , pp. 765 (first edition: 1891).
- ↑ a b Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: March 2020. (PDF 1729 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, March 2020, accessed March 7, 2020 .
- ↑ a b c d 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. 684 .
- ^ David Barthelmy: Zeophyllite Mineral Data. In: webmineral.com. Accessed March 7, 2020 (English).
- ↑ a b c Zeophyllite . 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; 80 kB ; accessed on March 7, 2020]).
- ↑ a b c Zeophyllite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 7, 2020 .
- ↑ 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 .
- ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF 1816 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed March 7, 2020 .
- ↑ Localities for Zeophyllite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 7, 2020 .
- ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia (= Dörfler Natur ). Edition Dörfler im Nebel-Verlag, Eggolsheim 2002, ISBN 978-3-89555-076-8 , p. 260 .
- ↑ List of locations for zeophyllite from the Mineralienatlas and Mindat , accessed on March 7, 2020.