Rudenkoit
| Rudenkoit | |
|---|---|
| General and classification | |
| other names |
IMA 2003-060 |
| chemical formula | Sr 3 Al 3 [(OH, O) 8 | Cl 2 | (Si, Al) 4 O 10 ] · H2O |
|
Mineral class (and possibly department) |
Silicates and Germanates |
|
System no. to Strunz and to Dana |
9.HA.50 ( 8th edition : VIII / G.07) 72.01.04.02 |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | prismatic 2 / m , sphenoid 2 or domatic m |
| Space group | Р 2 / m , Р 2 or Pm |
| Lattice parameters |
a = 5.893 (5) Å ; b = 7.262 (5) Å; c = 10.288 (8) Å β = 97.23 (3) ° |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 1.5 |
| Density (g / cm 3 ) | measured: 3.17; calculated: 3.18 |
| Cleavage | Please complete |
| colour | White |
| Line color | White |
| transparency | translucent |
| shine | Silky gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.693 (2) n β = 1.648 (2) n γ = 1.665 (2) |
| Birefringence | δ = 0.028 |
| Optical character | biaxial positive |
| Axis angle | 2V = 75 ° (measured); 72 ° (calculated) |
Rudenkoite is a very rare mineral from the mineral class of " silicates and germanates ". It crystallizes in the monoclinic crystal system with the composition of Sr 3 Al 3.5 Si 3.5 O 10 (ОН, O) 8 Cl 2 · Н 2 О, is thus seen a chemically complex composite and hydrated strontium - aluminum silicate. The elements indicated in the 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.
Rudenkoit develops spherical, fibrous mineral aggregates up to about 7 mm in size with a translucent white color and a silky, shiny surface.
Etymology and history
Was first discovered in the Rudenkoit phlogopite - deposit Emel'dzhak (Emeldzhakskoe) at Aldan in the Republic of Sakha (Yakutia, Russia) and described in 2004 by NV Chukanov, VT Dubinchuk, MN Murashko, AE Zadov and V. Yu. Karpenko, who named the mineral after Sergey Aleksandrovich Rudenko (1917–1992).
classification
Already in the now outdated, but still in use 8th edition of the mineral systematics according to Strunz , rudenkoite belonged to the mineral class of "silicates and germanates" and there to the department of "transition structures between chain and layered silicates", where together with bavenite , chiavennite , prehnite , Amstallit and Tvedalit formed the independent group VIII / G.07 .
The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the International Mineralogical Association (IMA), also assigns rudenkoite to the class of "silicates and germanates", although there it is in the "unclassified silicates" department. This division is also further subdivided according to the predominant metals in the compound, so that the mineral can be found according to its composition in the sub-division “With alkali and alkaline earth elements”, where it is the only member of the unnamed group 9.HA.50 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns Rudenkoit to the class of "silicates and Germanates", but there in the department of "layered silicates: two-dimensional unlimited layers with rings other than six-membered". Here it can be found together with Amstallite in the unnamed group 72.01.04 within the sub-section “ Layered silicates: two-dimensional unlimited layers with other than six-membered rings: 4-membered rings ”.
Education and Locations
Rudenkoit forms in metasomatically converted pyroxene - scapolite - rocks . Accompanying minerals include prehnite , calcite , spinel , apatite and diopside .
Apart from its type locality Emel'dzhak (Emeldzhakskoe) near Aldan in Russia, rudenkoite has not been found at any other site so far (as of 2011).
Crystal structure
Rudenkoite crystallizes monoclinically in the space group Р 2 / m , Р 2 or Pm with the lattice parameters a = 5.893 (5) Å ; b = 7.262 (5) Å; c = 10.288 (8) Å and β = 97.23 (3) ° as well as one formula unit per unit cell .
See also
Web links
Individual evidence
- ↑ a b c d e NV Chukanov, VT Dubinchuk, MN Murashko, AE Zadov, V. Yu. Karpenko: РУДЕНКОИТ Sr 3 Al 3,5 Si 3,5 O 10 (ОН 7,5 , O 0,5 ) Cl 2 · Н 2 О - НОВЫЙ МИНЕРАЛ ИЗ ФЛОГОПИТОВЫХ МЕСТОРОЖДЕНИЙ ЮЖНОЙ якутиkoit (translated: Ruden [...] a new mineral from phlogopite deposits of Southern Yakutia ), in: Zapiski Vserossijskogo Mineralogicheskogo Obshchestva , Volume 133, Chapter 3, pp. 37–41 ( PDF 296 kB )
- ↑ a b c d Mindat - Rudenkoite
- ↑ IMA / CNMNC List of Mineral Names - Rudenkoite (PDF 1.8 MB; p. 246)