Mordenite
| Mordenite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula |
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Mineral class (and possibly department) |
Silicates and Germanates - framework silicates (tectosilicates) |
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System no. to Strunz and to Dana |
9.GD.35 ( 8th edition : VIII / J.22) 77.01.06.01 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-pyramidal; mm 2 |
| Space group | Cmc 2 1 (No. 36) |
| Lattice parameters | a = 18.11 Å ; b = 20.46 Å; c = 7.52 Å |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 3 to 4 |
| Density (g / cm 3 ) | measured: 2.12 to 2.15; calculated: 2.125 |
| Cleavage | completely after {100}, indistinct {010} |
| Break ; Tenacity | uneven, brittle |
| colour | colorless, white, yellowish, pale pink |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass luster; Pearlescent to silk gloss for fibrous aggregates |
| Crystal optics | |
| Refractive indices |
n α = 1.472 to 1.483 n β = 1.475 to 1.485 n γ = 1.477 to 1.487 |
| Birefringence | δ = 0.005 |
| Optical character | alternating biaxially |
| Axis angle | 2V = measured: 76 to 104 °; calculated: 78 to 88 ° |
Mordenite is a rather seldom occurring mineral from the mineral class of " silicates and germanates " with the chemical composition (Na 2 , Ca, K 2 ) 4 (Al 8 Si 40 ) O 96 · 28H 2 O and is therefore chemically a water-containing sodium - Calcium - potassium silicate. The elements sodium, calcium and potassium indicated in round brackets can represent each other in the formula ( substitution , diadochie), but are always in the same proportion to the other components of the mineral. Structurally, mordenite belongs to the framework silicates ( tectosilicates ) and there to the group of zeolites .
Mordenite crystallizes in the orthorhombic crystal system and develops mostly prismatic to fine-needle-fibrous crystals up to about 2.5 cm in size in spherical mineral aggregates of white, yellowish or pale pink color with white streak color . Colorless crystals are also known.
Etymology and history
Mordenite was first discovered in one of the North Mountain Basalt outcrops along the Bay of Fundy near Morden in Kings County in the Canadian province of Nova Scotia . The mineral was described in 1864 by Henry How , who named the mineral after its type locality .
A mineral described by Cross and Eakins in 1886 and referred to as Ptilolite (English Ptilolite ) turned out to be identical to Mordenite in later analyzes. The name was therefore discredited and has been a synonym for mordenite ever since.
classification
In the outdated but still partially in use 8th edition of the mineral classification by Strunz of mordenite belonged to the mineral class of "silicates and Germanates" and there to the general ward of the " framework silicates (tectosilicates)" where he collaborated with boggsite , Dachiardit-Ca , Dachiardit -Na , Direnzoit , Edingtonit , Ferrierit-K , Ferrierit-Mg , Ferrierit-Na , Gottardiit , Laumontit , Mutinait and Terranovait the subgroup of "Fiber Zeolites II" with the system no. VIII / J.22 within the zeolite group .
Since 2001, fixed by the International Mineralogical Association used (IMA) 9th edition of Strunz'schen systematic mineral also assigns the mordenite in the class of "silicates and Germanates" there, however, in the department of the " framework silicates (tectosilicates) with zeolitic H 2 O; Family of zeolites ”. This is also further divided by the crystal structure, so that the mineral according to its construction in the subdivision "chains of five-rings" can be found, where it only with Maricopait after him "mordenite group" notified to the system no. 9.GD.35 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns mordenite to the class of "silicates and germanates" and there in the department of "framework silicates: zeolite group". Here he is together with Epistilbit , Maricopait , Dachiardit-Ca , Dachiardit-Na , Ferrierit-Mg , Ferrierit-K , Ferrierit-Na , Boggsit , Gottardiit , Terranovait , Mutinait and Direnzoit in the group named after him " Mordenite and related species " with the system no. 77.01.06 to be found in the sub-section of "Real Zeolites".
Crystal structure
Mordenite crystallizes orthorhombically in the space group Cmc 2 1 (space group no. 36) with the lattice parameters a = 18.11 Å ; b = 20.46 Å and c = 7.52 Å and one formula unit per unit cell .
properties
Occasionally mordenite shows a weak white fluorescence under UV light .
Education and Locations
Mordenite forms either in dikes and veins of igneous rocks, as a hydration product of volcanic glasses or in sedimentary rocks . Accompanying minerals include various zeolites, calcite , kaolinite and glauconite .
As a rather rare mineral formation, mordenite can sometimes be abundant at various sites, but overall it is not very common. Worldwide, around 330 sites are known to date (as of 2010). In addition to its type locality Morden, the mineral occurred in Canada at Cape Blomidon and Harbourville ( Bay of Fundy ) as well as in the Arlington quarry in Kings County and at Margaretsville in Annapolis County in the province of Nova Scotia. The mineral was also found in the province of Québec , more precisely in the "Demix-Varennes" quarry near Saint-Amable and some quarries near Montréal .
In Austria, Mordenite was found, among other things, in the construction of tunnels for the Süd Autobahn (A2) near Klagenfurt in Carinthia, on the Fellergraben in the Zederhaus Valley in Salzburg and on the Stradner Kogel , in the construction of the Tanzenberg tunnel , on the Weißen Sulm and in the Aldrian quarry near Oberhaag in Styria .
In Germany, the mineral has so far only been found on Wingertsberg near Nieder-Ramstadt in the Odenwald (Hesse).
Other locations include the Antarctic, Argentina, Australia, Brazil, Bulgaria, China, Costa Rica, Denmark, Ecuador, France, Greece, Greenland, Iceland, India, Italy, Japan, Canada, Mexico, New Zealand, Nicaragua, Portugal, in Réunion, Romania, Russia, Slovakia, Spain, South Africa, the Czech Republic, Turkey, Ukraine, Hungary, the United Kingdom (Great Britain), the United States of America (USA) and Cyprus.
Mordenite was also found in rock samples from the “ Ninety East Ridge ” from the Indian Ocean .
See also
literature
- H. How: On mordenite, a new mineral from the trap of Nova Scotia . In: Journal of the Chemical Society . tape 17 , 1864, p. 100–104 ( rruff.info [PDF; 292 kB ; accessed on September 28, 2017]).
Web links
- Mineral Atlas: Mordenite (Wiki)
- RRUFF Database-of-Raman-spectroscopy - Mordenite (English)
- American-Mineralogist-Crystal-Structure-Database - Mordenite (English)
Individual evidence
- ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
- ↑ a b IMA / CNMNC List of Mineral Names; July 2017 - Mordenite (PDF; 1.66 MB; p. 127)
- ↑ 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. 705 .
- ↑ Webmineral - Mordenite (English)
- ↑ a b c d e f Mindat - Mordenite (English)
- ^ W. Cross, LG Eakins: On ptilolite, a new mineral . In: American Journal of Science . tape 32 , no. 3 , 1886, p. 117-121 .
- ^ Arthur Roe, John S. White, Jr .: A Catalog of the Type Specimens in the Mineral Collection, National Museum of Natural History . Washington 1976, p. 33 ( si.edu [PDF; 4.0 MB ]).
- ↑ a b List of locations for mordenite in the Mineralienatlas and Mindat