Danalith
| Danalith | |
|---|---|
 |
|
| General and classification | |
| chemical formula |
|
|
Mineral class (and possibly department) |
Silicates and Germanates |
|
System no. to Strunz and to Dana |
9.FB.10 ( 8th edition : VIII / J.12) 76.02.04.02 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic-hexakistrahedral; 4 3 m |
| Room group (no.) | P 4 3 n (No. 218) |
| Lattice parameters | a = 8.23 Å |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 5.5 to 6 |
| Density (g / cm 3 ) | measured: 3.28 to 3.46; calculated: 3.36 |
| Cleavage | indistinct after {111}, {1 1 1} |
| Break ; Tenacity | slightly scalloped to uneven; brittle |
| colour | yellow, pink to red, reddish brown; colorless to pink in thin layers |
| Line color | white to off-white |
| transparency | translucent |
| shine | Glass gloss, fat gloss |
| Crystal optics | |
| Refractive index | n = 1.747 to 1.771 |
| Birefringence | none, as isotropic |
Danalith is a rarely occurring mineral from the mineral class of "silicates and germanates". It crystallizes in the cubic crystal system with the chemical composition Fe 4 [S | (BeSiO 4 ) 3 ], so it is chemically an iron - beryllium - silicate with sulfur as additional anions . Structurally danalite one of the framework silicates ( tectosilicates ).
Danalith is the iron analogue of the manganese-containing helvin (Mn 4 [S | (BeSiO 4 ) 3 ]) and zinc-containing genthelvin (Zn 4 [S | (BeSiO 4 ) 3 ]) and forms with each of them a continuous mixed crystal row . The mixed crystal formula is indicated accordingly with (Mn, Fe, Zn) 4 [S | (BeSiO 4 ) 3 ], whereby the elements indicated in the first round brackets can represent each other ( substitution , diadochie), but always in the same proportion the other formula components.
The mineral usually develops octahedral or dodecahedral crystals up to about 10 centimeters in size with a glass- to fat-like sheen on the surfaces. In its pure form, Danalith is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline training, it can also appear white and, due to foreign admixtures, take on a yellow, pink to red or reddish-brown color, the transparency decreasing accordingly.
Etymology and history
Danalith was first discovered in the granite quarries near Rockport in the US state of Massachusetts and described in 1866 by Joslah P. Cooke, Jr., who named the mineral after the famous mineralogist James Dwight Dana .
Type material of the mineral is found at Harvard University in Cambridge, Massachusetts (catalog number 85384) and at the National Museum of Natural History in Washington, DC in the USA (catalog number 124353) and at the Natural History Museum in London, England (catalog No. 1976,422).
classification
Already in the outdated but still partially in use 8th edition of the mineral classification by Strunz of danalite belonged to the mineral class of "silicates and Germanates" and then to the Department of "framework silicates (tectosilicates), with zeolites", where he together with Genthelvin and Helvin the "Helvin series" with the system no. VIII / J.12 formed.
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), classifies the danalith in the already more finely subdivided division of “tectosilicates without zeolitic H 2 O”. This is further subdivided according to the possible presence of additional anions, so that the mineral can be found according to its composition in the sub-section “Tectosilicates with additional anions”, where together with sodalite it is the “sodalite-danalite group” with the system -No. 9.FB.10 and the other members Bicchulith , Genthelvin, Haüyn , Helvin, Kamaishilith , Lasurit , Nosean , Tsaregorodtsevit and Tugtupit .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Danalith to the class of "silicates and germanates" and there in the department of "framework silicates: Al-Si lattice". Here he is again in the " Helving group " with the system no. 76.02.04 within the sub-section "Framework silicates: Al-Si lattices, feldspar representatives and related species".
Education and Locations
Danalith forms either magmatic in granites and granitic pegmatites or hydrothermally in gneisses , skarns and on ore tunnels . As accompanying minerals may vary by locality, among others, albite , cassiterite , pyrite and muscovite in tin pegmatites; Garnet , fluorite and magnetite (in skarn) or arsenopyrite , chlorite and quartz (in hydrothermal deposits) occur.
As a rare mineral formation, Danalith could only be detected at a few sites, whereby so far (as of 2014) around 60 sites are known. In addition to its Rockport type , the mineral appeared in Massachusetts in several places around Gloucester . It was also found in the United States at Jerome in Yavapai County of Arizona; in the Cheyenne District and on Stove Mountain in El Paso County, Colorado ; in several locations in Carroll County, New Hampshire ; at Victorio in Luna County , Iron Mountain in Sierra County and the Harding Mine in Taos County , New Mexico.
In Germany, Danalith could so far only be found at Krennbruch in the Lower Bavarian municipality of Saldenburg and in Schurf 24 at the Schwarzenberg dome near Pöhla in Saxony.
The only known site in Austria so far is the “Poschacher” quarry near Artolz in the Lower Austrian municipality of Pfaffenschlag near Waidhofen an der Thaya .
Other localities include Argentina, Australia, Brazil, China, Finland, Japan, Canada, Kazakhstan, Norway, Russia, Sweden, Somalia and the United Kingdom (England, Northern Ireland).
Crystal structure
Danalith crystallizes cubically in the space group P 4 3 n (space group no. 218) with the lattice parameter a = 8.23 Å and two formula units per unit cell .
See also
literature
- Joslah P. Cooke, Jr .: On danalite, a new mineral species from the Granit of Rockport, Mass. In: American Journal of Science and Arts. Volume 92 (1866), pp. 73–79 ( PDF 392.5 kB )
- Donald M. Burt: The stability of danalite, Fe 4 Be 3 (SiO 4 ) 3 S. In: American Mineralogist. Volume 65 (1980), pp. 355-360 ( PDF 400.6 kB )
- Sytle M. Antao, Ishmael Hassan, John B. Parise: The structure of danalite at high temperature obtained from synchrotron radiation and Rietveld refinements. In: The Canadian Mineralogist. Volume 41 (2003), pp. 1413–1422 ( PDF 692.12 kB )
- Hans Jürgen Rösler : Textbook of Mineralogy . 4th revised and expanded edition. German publishing house for basic industry (VEB), Leipzig 1987, ISBN 3-342-00288-3 , p. 545 .
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 269 ( Dörfler Natur ).
Web links
- Mineral Atlas: Danalith (Wiki)
- Webmineral - Danalite
- Database-of-Raman-spectroscopy - Danalite
- American-Mineralogist-Crystal-Structure-Database - Danalite
Individual evidence
- ↑ a b c d e f g 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. 699 .
- ^ IMA / CNMNC List of Mineral Names; January 2014 (PDF 1.5 MB)
- ↑ a b c Danalite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 71.2 kB )
- ↑ Mindat - Dana Lite
- ↑ Mindat - Number of localities for Danalith
- ↑ Find location list for Danalith at the Mineralienatlas and at Mindat