Phosphuranylite
| Phosphuranylite | |
|---|---|
 |
|
| General and classification | |
| chemical formula | KCa (H 3 O) 3 (UO 2 ) 7 (PO 4 ) 4 O 4 · 8H 2 O |
|
Mineral class (and possibly department) |
Phosphates, arsenates, vanadates |
|
System no. to Strunz and to Dana |
8.EC.10 ( 8th edition : 7 / E.07-30) 42.4.8.1 |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; mmm |
| Room group (no.) | Cmcm (No. 63) |
| Lattice parameters | a = 15.78 Å ; b = 13.70 Å; c = 17.25 Å |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 2.5 |
| Density (g / cm 3 ) | measured: 4.1; calculated: 4.6 |
| Cleavage | completely parallel to the flat |
| Break ; Tenacity | brittle |
| colour | golden yellow, dark yellow, lemon yellow |
| Line color | light yellow |
| transparency | translucent |
| shine | waxy, silky gloss |
| radioactivity | 114.078 k Bq / g |
| Crystal optics | |
| Refractive indices |
n α = 1.658 to 1.695 n β = 1.699 to 1.770 n γ = 1.699 to 1.770 |
| Birefringence | δ = 0.041 to 0.075 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 5 ° to 35 ° |
| Pleochroism | visible: X = colorless to light yellow, Y = golden yellow, Z = golden yellow |
| Other properties | |
| Chemical behavior | soluble in acids |
Phosphuranylite is a rather rare mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the orthorhombic crystal system with the chemical composition KCa (H 3 O) 3 (UO 2 ) 7 (PO 4 ) 4 O 4 · 8H 2 O and is therefore chemically a water-containing potassium - calcium - uranyl phosphate.
The mineral develops tabular and elongated crystals up to about two millimeters in diameter, which are usually connected to thin tabular mineral aggregates and crusty coatings. The translucent crystals are golden yellow, also dark to lemon yellow in color with a light yellow streak color and have a waxy, even silky sheen on the surfaces .
Etymology and history
Phosphuranylite was first described in 1879 by the German-American chemist and mineralogist Friedrich August Genth . His samples came from Flat Rock in Mitchell County ( North Carolina , United States ); he named the mineral after the elements phosphorus and (uranyl) uranium in their chemical composition.
Type material of the mineral is held at Pennsylvania State University and Yale University under catalog number 3249-3251.
classification
Already in the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the phosphuranylite belonged to the mineral class of "phosphates, arsenates, vanadates" and there to the department of "uranyl phosphates and uranyl vanadates", where together with althupit , arsenuranylite , bergenite , Dewindtit , Dumontit , Françoisit- (Ce) , Françoisit- (Nd) , Hügelite , Kamitugait , Kivuit , Metavanmeer log , Mundit , Yingjiangit , Phuralumit , Phurcalit and Vanmeersscheit formed the unnamed group VII / E.07 .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also assigns phosphuranylite to the class of "phosphates, arsenates and vanadates" and there in the department of "uranyl phosphates and arsenates". However, this section is further subdivided according to the molar ratio of uranium oxide complex (UO 2 ) and phosphate or arsenate complex (RO 4 ), so that the mineral can be found in the sub-section "UO 2 : RO 4 = 3: 2" according to its composition , where together with arsenuranylite, bergenite, dewindtite, yingjiangite, phurcalite and renardite, the "phosphuranylite-phurcalite group" with the system no. 8.EC.10 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns phosphuranylite to the class of "phosphates, arsenates, vanadates", but there it belongs to the category of "water-containing phosphates, etc., with hydroxyl or halogen". Here he is to be found as the only member of the unnamed group April 42, 2008 within the subdivision of " Water-containing phosphates etc., with hydroxyl or halogen with (AB) 5 (XO 4 ) 2 Z q × x (H 2 O) " .
Crystal structure
Phosphuranylite crystallizes orthorhombically in the space group Cmcm (space group no. 63) with the lattice parameters a = 15.78 Å ; b = 13.70 Å, c = 17.25 Å and β = 90 ° as well as 4 formula units per unit cell .
properties
The mineral is radioactive due to its uranium content of up to 63.67% . Taking into account the natural series of decay or any decay products present, the specific activity is given as 114.078 k Bq / g (for comparison: natural potassium 0.0312 kBq / g). The quoted value can vary significantly depending on the mineral content and composition of the levels; selective enrichment or depletion of the radioactive decay products is also possible and changes the activity. Fluorescence does not occur under UV light, on some samples only due to accompanying minerals such as Autunit .
Education and Locations
Phosphuranylite is produced as a secondary mineral in the oxidation zone of uranium deposits . Accompanying minerals include Autunit , Uranophane , Becquerelite , Curit , Parsonsite , Torbernite , Saléeit , Sabugalite and Haiweeit . In addition to its type locality Buchanan Mine, North Carolina, the mineral was also found in the United States in the Ruggles Mine near Grafton , and in the Palermo # 1 Mine near New Groton, New Hampshire ; in Brazil in Minas Gerais in the pegmatites of Enio and Córrego do Urucum, in Italy near Peveragno , Arcu su Linnarbu and Cagliari; in France in the mines La Crouzille and Margnac near Compreignac and near Bois Noirs (Loire), also near Wölsendorf in Germany, Carrasca, Mangualde and Sabugal in Portugal , Shinkolobwe Mine (Katanga Province) and Kobokobo Pegmatit (Kivu Province) in the Democratic Republic Congo ; near Vatovory in Madagascar and the Saddle Ridge Mine (South Alligator Valley) in Australia .
Precautions
Due to the toxicity and the strong radioactivity of the mineral, mineral samples of phosphuranylite should only be kept in dust- and radiation-tight 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: Phosphuranylite
- Database-of-Raman-spectroscopy - Phosphuranylite
- American-Mineralogist-Crystal-Structure-Database - Phosphuranylite
Individual evidence
- ↑ a b c Webmineral - Phosphuranylite
- ↑ a b c d e f g h Mindat - Phosphuranylite
- ↑ a b Mineralienatlas - Phosphuranylit
- ↑ a b c Phosphuranylite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 67 kB )