Natrozippeit
| Natrozippeit | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1971-004 |
| chemical formula | Na 4 (UO 2 ) 6 (SO 4 ) 3 (OH) 10 · 4H 2 O |
|
Mineral class (and possibly department) |
Sulphates (selenates, tellurates, chromates, molybdates, wolframates) (formerly sulfates, chromates, molybdates and tungstates) |
|
System no. to Strunz and to Dana |
7.EC.05 ( 8th edition : VI / D.20) 31.10.4.2 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | 2 / m |
| Room group (no.) | n. d. (No. n. D.) |
| Lattice parameters | a = 8.82 Å ; b = 17.12 Å; c = 7.32 Å |
| Physical Properties | |
| Mohs hardness | 2 |
| Density (g / cm 3 ) | 3.3 to 4.3 |
| Cleavage | perfectly |
| colour | yellow, yellow-orange, yellow-green |
| Line color | yellow |
| transparency | translucent |
| shine | matt, earthy |
| radioactivity | very strong |
| Crystal optics | |
| Refractive indices |
n α = 1.630 to 1.637 n β = 1.685 to 1.689 n γ = 1.732 to 1.739 |
| Birefringence | δ = 0.102 |
Natrozippeit (also sodium zippeit ) is a rather rare mineral from the mineral class of sulfates, selenates, tellurates, chromates, molybdates and tungstates (formerly sulfates, chromates, molybdates and tungstates). It crystallizes in the orthorhombic crystal system with the chemical composition Na 4 (UO 2 ) 6 (SO 4 ) 3 (OH) 10 · 4H 2 O.
Natrozippeit only develops tiny crystals up to about 0.1 millimeter in diameter with a rhombic, elongated and thin tabular habit . It usually consists of fused platelets, worm-like or powdery mineral aggregates and also occurs in the form of granular and crusty coatings. The lemon-yellow, yellowish-orange, rarely also greenish-yellow crystals are translucent with matt crystal surfaces. Natrozippeit leaves a yellow line on the notice board .
Demarcation
Zippeit is one of the six minerals of the Zippeit group 7.EC.05 in the 9th edition of Strunz's mineral classification, but is usually generalized by mistake.
Etymology and history
Natrozippeit was named in honor of the Bohemian natural scientist Franz Xaver Zippe after him and is also a result of its chemical composition. The name Zippeit was first named by Haidinger in 1845 for an earthy, yellow uranyl sulfate from Jáchymov (German Sankt Joachimsthal ) in the Czech Republic , which was already described by John in 1821. Only more detailed investigations by Clifford Frondel in 1976 gave more precise information about the chemical composition and occupation of the Zippeit group , so that all mentions in the literature before this point in time are very unspecific or were even assigned only according to their appearance.
classification
In the outdated, but partly still in use, 8th edition of the mineral classification according to Strunz , the natrozippite belonged to the common mineral class of "sulfates, selenates, tellurates, chromates, molybdates and tungstates" and there to the department of "hydrous sulfates with foreign anions" where it belongs together with Cobaltzippeit , Jáchymovit , Uranopilite , Magnesiumzippeit , Marécottit , Metauranopilit , Nickelzippeit , Rabejacit , Zinkzippeit and Zippeit the Uranopilite group VI / D.20 formed.
The 9th edition of Strunz's mineral systematics , which has been in force since 2001 and is used by the International Mineralogical Association (IMA), assigns natrozippeit to the class of "sulfates, selenates, tellurates, chromates, molybdates and wolframates", but in the department of "Uranyl Sulphate". This is further subdivided so that the mineral can be found according to its composition in the sub-section “With medium-sized and large cations”, where it is located as a member of group 7.EC.05 with the cobalt zippeit, magnesio zipp time, nickel zipp time, zinc zipp time and zipp time .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns natrozippeite to the class of "sulfates, chromates and molybdates" and there in the category of "water-containing sulfates with hydroxyl or halogen". Here he can be found as a member of the Zippeit group within the sub-section “Various hydrous sulphates with hydroxyl or halogen”.
Crystal structure
Natrozippeite crystallizes orthorhombically in an as yet undefined space group with the lattice parameters a = 8.82 Å , b = 17.12 Å and c = 7.32 Å.
properties
Due to its uranium content of up to 58.1%, the mineral is very radioactive . Taking into account the proportions of radioactive elements in the idealized empirical formula as well as the subsequent decays of the natural decay series, a specific activity of 103.98 k Bq / g is specified for the mineral (for comparison: natural potassium 31.2 Bq / g). The quoted value can vary significantly depending on the mineral content and the composition of the levels; selective enrichment or depletion of the radioactive decay products is also possible and changes the activity. Natrozippeite is readily soluble in acids and shows yellow fluorescence under UV light .
Modifications and varieties
Natrozippeite with the chemical composition Na 5 (UO 2 ) 8 (SO 4 ) 4 O 5 (OH) 3 · 12H 2 O is a modification with a Mohs hardness of 5 - 5.5 and crystallizes in the monoclinic crystal system . PC Burns et al. presented these synthetically in order to investigate its chemical structure and crystal chemistry .
Education and Locations
Natrozippeite forms as a secondary mineral in the oxidation zones of uranium deposits. Accompanying minerals include Andersonite , Uranopilit , Johannit , Schröckingerit and other representatives of the "Zippeit Group". Its type locality is in the Happy Jack Mine , White Canyon , Utah , USA . Other previously known sites are Geevor Mine near St.Just in England , Rožná , Jáchymov and in Jánská žíla near Příbram in the Czech Republic and La Creusaz in Switzerland .
Precautions
Due to the toxicity and the strong radioactivity of the mineral, mineral samples from Natrozippeit should only be kept in dust- and radiation-proof containers, but especially never in living rooms, bedrooms or work rooms. Absorption into the body (incorporation, ingestion ) should also be prevented in any case and, for safety, direct body contact should be avoided and respiratory protection mask and gloves should be worn when handling the mineral .
See also
Web links
- Mineral Atlas: Natrozippeite (Wiki)
Individual evidence
- ↑ a b c d Webmineral - Natrozippeite
- ↑ a b c d e f g John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( Sodium-zippeite (PDF, English 64.7 kB) )
- ↑ a b c Mindat - Natrozippeite
- ^ NJ Elton, JJ Hooper: Sodium-zippeite from Geevor mine, St. Just, Cornwall In: Mineralogical Magazine 1993, 57, pp. 352-354. ( PDF (English) 1.7 MB )
- ^ Ray L. Frost, Jiří Čejka, Godwin A. Ayoko and Matt L. Weier: Raman spectroscopic and SEM analysis of sodium zippeite In: Journal of Raman Spectroscopy 2007, 38 (10), pp. 1311-1319. ( PDF (English) 418 kB )
- ↑ PC Burns, Kathryn M. Deely, Leslie A. Hayden: The Crystal Chemistry of the Zippeite Group In: The Canadian Mineralogist 2003, 41, pp. 687-706. ( PDF (English) 3.3 MB )