Zirsinalite
| Zirsinalite | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1973-025 |
| chemical formula |
|
|
Mineral class (and possibly department) |
Silicates and germanates - ring silicates (cyclosilicates) |
|
System no. to Strunz and to Dana |
9.CJ.15 ( 8th edition : VIII / E.16) 61.01.02a.04 |
| Crystallographic Data | |
| Crystal system | trigonal |
| Crystal class ; symbol | ditrigonal-scalenohedral; 3 2 / m |
| Space group | R 3 m (No. 166) |
| Lattice parameters | a = 10.29 Å ; c = 13.11 Å |
| Formula units | Z = 3 |
| Physical Properties | |
| Mohs hardness | 5.5 ( VHN = 640-720) |
| Density (g / cm 3 ) | measured: 2.88 to 2.92; calculated: 3.08 |
| Cleavage | no |
| Break ; Tenacity | uneven to slightly scalloped |
| colour | colorless to white, pale yellowish gray |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n ω = 1.624 n ε = 1.590 to 1.592 |
| Birefringence | δ = 0.034 |
| Optical character | uniaxial negative |
Zirsinalith is a very rarely occurring minerals from the mineral class of "silicates and germanates" with the idealized chemical composition Na 6 CaZrSi 6 O 18 and is thus chemically seen a sodium - calcium - Zirconium - silicate that is structurally to the ring silicates belongs. However, since part of the calcium in natural zirsinalites can often be replaced ( substituted ) by manganese and / or iron , the formula is also used in various sources with Na 6 (Ca, Mn 2+ , Fe 2+ ) Zr [Si 6 O 18 ] ( Formula notation according to Strunz ).
Zirsinalite crystallizes in the trigonal crystal system , but has so far only been found in the form of irregular mineral aggregates and rounded, irregular grains of up to 7 cm × 5 cm in size. In its pure form, zirsinalite is colorless and transparent with a glass-like sheen on the surfaces. However, due to multiple refraction due to lattice construction defects or polycrystalline design , it can also appear white and, due to foreign admixtures, take on a slightly yellowish-gray color, the transparency decreasing accordingly.
With a Mohs hardness of 5.5, zirsinalite is one of the medium-hard minerals that are slightly easier to scratch than the reference mineral orthoclase (hardness 6) with a steel file or slightly worse than the reference mineral apatite (hardness 5) with a pocket knife .
Etymology and history
The name Zirsinalith is a case word , consisting of the abbreviations of chemical constituents zir conium, Si Licium and Na trium with the addition lithos for "stone" (Greek λίθος).
Zirsinalite was first discovered in 1965 in the mineral samples of a drill core that was recovered from a depth of 180 m on the east face of Mount Koaschwa . This is part of the Chibinen mountain range on the Russian Kola peninsula , part of the Murmansk Oblast . The analysis and initial description of the mineral was carried out by Yu. L. Kapustin, ZV Pudovkina and AV Bykova, who submitted their test results and the chosen name to the International Mineralogical Association (IMA) for examination in 1973 (IMA internal accession number : 1973-025 ), who registered the Coloradoite in the same year as independent mineral type recognized. The first description was published a year later in the Russian journal Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva .
The type material of the mineral in which, the Russian Academy of Sciences connected, Fersman Museum (named after Alexander Fersman ) in Moscow under catalog no. 75149 kept.
classification
Already in the outdated, but partly still in use 8th edition of the mineral systematics according to Strunz , the zirsinalite belonged to the mineral class of "silicates and germanates" and there to the division of "ring silicates (cyclosilicates)", where it together with Imandrite , Kazakovit , Kapustinit , Koashvit , Litvinskit , Lovozerit , Petarasit and Tisinalith the "Lovozeritgruppe" with the system no. VIII / E.16 .
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the IMA, also classifies zirsinalite in the "ring silicates" section. However, this is further subdivided according to the structure of the rings and the possible presence of additional anions , so that the mineral can be found according to its composition in the subsection "[Si 6 O 18 ] 12− -six-simple rings without island-like, complex anions", where together with Combeit , Kapustinit, Kazakovit , Litvinskit, Lovozerit and Tisinalit the "Combeit-Lovozerit-Gruppe" with the system no. 9.CJ.15 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the zirsinalite to the class of "silicates and Germanates" and there in the category of "ring silicates: six rings". Here he is together with in the " Lovozeritgruppe (hexagonal and hexagonal-rhombohedral subgroup) " with the system no. 61.01.02a within the sub-section “ Ring Silicates : Six Rings with Si 6 O 18 Rings; possible (OH) and Al substitution ”.
Chemism
In the idealized composition Na 6 CaZrSi 6 O 18 , zirsinalite consists of 25.62% by weight of Na 2 O , 7.73% by weight of CaO , 16.98% by weight of ZrO 2 and 49.67 % by weight. % SiO 2 .
In the analysis of the Koaschwa type material, however, a clear proportion of manganese in the form of MnO from 2.60 to 2.62% by weight and iron in the form of FeO from 0.40 to 0.8% by weight was found . In addition, traces of titanium were found in the form of TiO 2 from 0.4 to 0.56% by weight and water (H 2 O) from 0.80 to 0.90% by weight, which corresponds to the idealized empirical formula Na 6 (Ca, Mn, Fe) ZrSi 6 O 18 corresponds.
Crystal structure
Zirsinalite crystallizes trigonally in the space group R 3 m (space group no. 166) with the lattice parameters a = 10.29 Å and c = 13.11 Å as well as three formula units per unit cell .
properties
Zirsinalite is slowly decomposed by cold, diluted acids. In contrast, in 10% hydrochloric acid (HCl) or sulfuric acid (H 2 SO 4 ) heated to 60-80 °, the mineral is easily decomposed, with gelatinous silica separating out. Zirsinalite is leached in cold water, i.e. finely ground material loses 1.71% sodium in just a few hours. After a week, the sodium loss increases to 2.91%. Nevertheless, the residue shows the same X-ray pattern as the original substance. Hot water leaches 3.0% sodium after just one hour, with the DTA and TG curves showing a small endothermic pause at 300 ° C, which corresponds to a weight loss of 1%. When heated to around 1000 ° C, zirsinalite melts into a white enamel pearl.
In the air, the mineral corrodes quickly, forming a powdery coating of sodium carbonate .
Education and Locations
Zirsinalite forms in pegmatitic veins that penetrate alkaline rocks in differentiated alkali massifs. Since zirsinalite is replaced by loozerite and eudialyte over time, the mineral is mainly found in association with these . Also pseudomorphic of Zirsinalith after Eudialyt are known for this reason. Other known accompanying minerals include aegirine , anorthoclase , catapleiite , barium-containing lamprophyllite , lomonosovite , nepheline and shcherbakovite .
The most important rocks on Koaschwa are apatite - nephelinite with carbonatite , urtite and foidolite . The rich apatite deposit is being mined in the nearby open-cast mine of the same name , in which a total of 107 minerals and varieties have been found so far and which, including zirsinalite, is the type locality for 29 minerals so far (status 2018).
As a very rare mineral formation, zirsinalite could only be detected in a few samples from around 10 sites, all of which are on the Russian Kola peninsula . In addition to the Koaschwa, these include the alkali pegmatites on the Kukiswumtschorr , the Raswumtschorr and the Apatitovyi Tsirk and Centralnyi , Yukspor pits and in the Vuonnemiok river valley near the Imandra lake in the Chibinen mountain range . In addition there are the mountains Karnassurt and Alluaiw (see picture in the info box) in the mountain range of the Lowosero-Tundra
See also
literature
- Yu. L. Kapustin, ZV Pudovkina, AV Bykova: Zirsinalite, a new mineral . In: International Geology Review . tape 17 , no. 7 , 1975, p. 807–812 , doi : 10.1080 / 00206817509471633 (English, Russian: Tsirsinalit - novyy mineral . Moscow 1974. Translated by Michael Fleischer , original collection: Zapiski Vserossiyskogo Mineralogicheskogo Obshchestva , Volume 103, No. 5, pp. 559-566).
- Michael Fleischer, GY Chao, Ikiro Kato: New Mineral Names . In: American Mineralogist . tape 60 , no. 5-6 , 1975, pp. 485–489 (English, minsocam.org [PDF; 623 kB ; accessed on August 3, 2018]).
- ZV Pudovkina, NM Chernitsova, AA Voronkov, Yu. A. Pyatenko: Crystal structure of zirsinalite Na 6 Ca {Zr (Si 6 O 18 )} . In: Doklady Akademii Nauk SSSR . tape 250 , 1980, pp. 865-867 (English).
Web links
- Mineral Atlas: Zirsinalite (Wiki)
- Webmineral - Zirsinalite (English)
- American-Mineralogist-Crystal-Structure-Database - Zirsinalite (English)
- Цирсиналит (zirsinalite) on wiki.web.ru
Individual evidence
- ↑ a b IMA / CNMNC List of Mineral Names; March 2018 (PDF 1.65 MB)
- ↑ 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. 607 (English).
- ↑ a b c d Zirsinalite . 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; 59 kB ; accessed on July 15, 2018]).
- ↑ a b c d e Michael Fleischer , GY Chao, Ikiro Kato: New Mineral Names . In: American Mineralogist . tape 60 , no. 5-6 , 1975, pp. 485–489 (English, minsocam.org [PDF; 623 kB ; accessed on August 3, 2018]).
- ↑ a b 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 c Mindat - Zirsinalite (English)
- ^ A b c Igor V. Pekov: Minerals first discovered on the territory of the former Soviet Union . 1st edition. Ocean Pictures, Moscow 1998, ISBN 5-900395-16-2 , pp. 243 (English).
- ↑ Mindat - type locality Koashva Open Pit (Vostochnyi Mine)
- ↑ Find location list for zirsinalite at the Mineralienatlas and at Mindat