Weloganite
| Weloganite | |
|---|---|
 |
|
| General and classification | |
| other names |
IMA 1967-042 |
| chemical formula | Sr 3 Na 2 Zr [CO 3 ] 6 • 3H 2 O |
|
Mineral class (and possibly department) |
Carbonates and nitrates |
|
System no. to Strunz and to Dana |
5.CC.05 ( 8th edition : V / D.04) 03/15/04/04 |
| Crystallographic Data | |
| Crystal system | triclinic |
| Crystal class ; symbol | triklin-pedial; 1 |
| Room group (no.) | P 1 (No. 1) |
| Lattice parameters |
a = 8.97 Å ; b = 8.98 Å; c = 6.73 Å, α = 102.7 °; β = 116.6 °; γ = 60.1 ° |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 3.5 |
| Density (g / cm 3 ) | measured: 3.20 to 3.22; calculated: 3.208 |
| Cleavage | completely after pseudo- {0001} |
| Break ; Tenacity | shell-like |
| colour | colorless, white, light yellow to lemon yellow, amber colored |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.558 n β = 1.646 n γ = 1.640 |
| Birefringence | δ = 0.082 |
| Optical character | biaxial negative |
| Axis angle | 2V = 15 ° (measured) |
| Other properties | |
| Special features | pyroelectric, triboluminescent |
Weloganite is a very rarely occurring mineral from the mineral class of "carbonates and nitrates". It crystallizes in the triclinic crystal system with the chemical composition of Sr 3 Na 2 Zr [CO 3 ] 6 · 3H 2 O and is therefore chemically seen a water-containing strontium - sodium - Zirconium - carbonate .
Weloganit usually develops coarse crystalline , pseudo-hexagonal prisms with tapering, pyramidal ends and strongly corrugated, glass- glossy surfaces. In its pure form, weloganite is colorless and transparent. However, due to multiple refraction due to lattice construction defects or polycrystalline formation, it can also appear white and, due to foreign admixtures, take on a light yellow to lemon yellow or amber-like color, with the transparency decreasing accordingly.
Special properties
Weloganite is pyroelectric , which means that it reacts to periodically changing temperature changes by building up an electrical voltage . The mineral is also triboluminescent , so it emits a blue, cold glowing light when subjected to strong mechanical stress (friction).
Etymology and history
Weloganite was first discovered in 1966 in the "Francon" quarry near Montreal in the Canadian province of Québec and described in 1968 by Ann P. Sabina, John Leslie Jambor , AG Plant, who named the mineral after Sir William Edmond Logan (1798-1875), the founder and first director of the Geological Survey of Canada .
The type material of the mineral is kept in the Geological Survey of Canada (Catalog No. 17257, 61337).
classification
In the 8th edition of the mineral systematics according to Strunz , which is outdated but still in use , weloganite still belonged to the common mineral class of "carbonates, nitrates and borates" and there to the department of "hydrous carbonates without foreign anions ", where it was named after the "weloganite group" “With the system no. V / D.04 and the other members Donnayit- (Y) , Ewaldit , Mckelveyit- (Nd) and Mckelveyit- (Y) .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns weloganite to the newly defined class of “carbonates and nitrates”, but also to the “carbonates without additional anions” section; with H 2 O “. This is, however, further subdivided according to the relative size of the cations involved and / or the metals primarily involved in the connection, so that the mineral can be found in the sub-section “With rare earth elements (REE)”, where it can be found together with Donnayit- (Y), Mckelveyit- (Nd) and Mckelveyit- (Y) the "Donnayit group" with the system no. 5.CC.05 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns weloganite, like the outdated Strunz system, to the common class of “carbonates, nitrates and borates” and there to the department of “water-containing carbonates”. Here it is also together with Donnayit- (Y), Mckelveyit- (Nd) and Mckelveyit- (Y) in the " Mckelveyite group " with the system no. 03/15/04 within the sub-section “ Hydrous carbonates with A + m B 2+ n (XO 3 ) p • x (H 2 O), (m + n): p = 1: 1 and with U, Th, Zr, Y " to find.
Education and Locations
Weloganite is formed by hydrothermal processes in alkaline storage channels ( sill ). As Begleitminerale among others can calcite , dawsonite , Dresserit , quartz and zircon occur.
At its type locality , the “Francon” ( Francon quarry ) quarry near Montreal , weloganite crystals up to five centimeters in size emerged and crystals up to three centimeters in size were found near Saint-Michel near Montreal. In addition, the mineral is only known from the “Lafarge Montreal East” quarry and from the “Poudrette” quarry on Mont Saint-Hilaire in the province of Québec and from the “Eden Lake Complex” in the province of Manitoba in Canada (as of 2014). However, the largest known crystals are said to have had a length of 10 centimeters.
Another possible location is the Pilanesberg alkali complex near Rustenburg in the South African province of northwest , but this location has not yet been confirmed.
Crystal structure
Weloganite crystallizes triclinically in the space group P 1 (space group no. 1) with the lattice parameters a = 8.97 Å ; b = 8.98 Å; c = 6.73 Å; α = 102.7 °; β = 116.6 ° and γ = 60.1 ° and one formula unit per unit cell .
See also
literature
- Ann P. Sabina, John Leslie Jambor , AG Plant: Weloganite, a new strontium zirconium carbonate from Montreal Island, Canada. In: The Canadian Mineralogist. Volume 9 (1968), pp. 468-477 ( PDF 649.9 kB )
- JD Grice, G. Perrault: The crystal structure of triclinic weloganite. In: The Canadian Mineralogist. Volume 13 (1975), pp. 209-216 ( PDF 522 kB )
Web links
- Mineral Atlas: Weloganite (Wiki)
- Webmineral - Weloganite
- Database-of-Raman-spectroscopy - Weloganite
- American-Mineralogist-Crystal-Structure-Database - Weloganite
Individual evidence
- ↑ a b c d e 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. 307 .
- ↑ a b c d e Weloganite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 67.5 kB )
- ↑ a b c d Mindat - Weloganite
- ↑ Petr Korbel, Milan Novák: Mineral Encyclopedia . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 126 ( Dörfler Natur ).
- ↑ a b List of sites for weloganite in the Mineralienatlas and Mindat