Martinite
| Martinite | |
|---|---|
 (largest diameter of the leafy martinite aggregate: approx. ~ 2¼ mm) |
|
| General and classification | |
| other names |
IMA 2001-059 |
| chemical formula | (Na, [], Ca) 12 Ca 4 (Si, S, B) 14 B 2 O 38 (OH, Cl) 2 F 2 · 4H 2 O |
|
Mineral class (and possibly department) |
Silicates and Germanates |
|
System no. to Strunz and to Dana |
9.EE.80 ( 8th edition : VIII / H.34) 73.02.02d.01 |
| Crystallographic Data | |
| Crystal system | triclinic |
| Crystal class ; symbol | triclinic pinacoidal; 1 |
| Room group (no.) | P 1 (No. 2) |
| Lattice parameters |
a = 9.5437 (7) Å ; b = 9.5349 (6) Å; c = 14.0268 (10) Å α = 108.943 (1) °; β = 74.154 (1) °; γ = 119.780 (1) ° |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 4th |
| Density (g / cm 3 ) | calculated: 2.51 |
| Cleavage | completely after {001} |
| Break ; Tenacity | uneven; brittle |
| colour | colorless, white, purple |
| Line color | White |
| transparency | transparent |
| shine | Glass gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.529 (1) n β = 1.549 (1) n γ = 1.551 (1) |
| Optical character | biaxial negative |
| Axis angle | 2V = 38 (1) ° |
Martinite is a very rarely occurring mineral from the mineral class of " silicates and germanates ". It crystallizes in the triclinic crystal system with the chemical composition (Na, [], Ca) 12 Ca 4 (Si, S, B) 14 B 2 O 38 (OH, Cl) 2 F 2 · 4H 2 O and belongs to it because of its crystal structure the sheet silicates (phyllosilicates). 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.
Martinite develops triangular to hexagonal, tabular crystals , which are usually arranged in the form of rosette-shaped mineral aggregates with a diameter between 50 micrometers to one millimeter. In its pure form it is colorless and transparent. However, due to multiple refraction due to lattice construction defects or multicrystalline formation, it can also appear white and take on a purple color due to foreign admixtures. However, its line color is always white.
Etymology and history
Martinite was first discovered in 2001 in the "Poudrette quarry" on Mont Saint-Hilaire in the Canadian province of Québec and described by Andrew M. McDonald, George Y. Chao, who named the mineral after Robert François Martin (* 1941), professor of geology from McGill University and longtime editor of the Canadian Mineralogist .
McDonald and Chao submitted their test results as well as the chosen name to the International Mineralogical Association (IMA) for examination (register no. IMA 2001-059 ). This recognized the mineral in 2004 under the name martinite as independent. The publication of the newly discovered and recognized mineral followed in 2007 in the Canadian Mineralogist.
classification
Since the martinite was only recognized as an independent mineral in 2004, it is not listed in the Strunz mineral system (8th edition), which has been outdated since 2001 . Only the "Lapis mineral directory" published in 2008, which is still based on the classic system of Karl Hugo Strunz out of consideration for private collectors and institutional collections , lists the mineral under system no. VIII / H.34-29 .
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 martinite to the class of “silicates and germanates” and then to the “phyllosilicates” section. This department is, however, further subdivided according to the crystal structure, so that the mineral, according to its structure, can be found in the subdivision "Simple tetrahedral nets made of six-fold rings, connected by octahedral nets or ribbons", where together with fedorite it belongs to the unnamed group 9. EE.80 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns martinite to the class of "silicates and germanates" and there to the category of "layered silicates with condensed tetrahedral layers". Here he is together with Lalondeit in the "Reyerite group (Trikline subgroup)" with the system no. 73.02.02d can be found in the subsection of " Layered Silicates: Condensed Tetrahedral Layers with Double and Single Layers ".
Education and Locations
Martinite is formed through a complex interaction of highly fractionated , hyperagpaitic fluids with sodalite - syenite - xenolites . Begleitminerale include Aegirin , albite , Erdit , galena , Langit , Lueshit , molybdenite , Posnjakit , Rasvumit , Serandit , sphalerite , Terskit , ussingite , Villiaumit and wurtzite .
Apart from its type locality “Poudrette quarry” on Mont Saint-Hilaire in Canada, only one other site in Turkey, more precisely the “Murdere deposit” near Köprüköy (Kurdish: Avnîk) in Eastern Anatolia, has been known to date (as of 2012) .
Crystal structure
Martinite crystallizes triclinically in the space group P 1 (space group no. 2) with the lattice parameters a = 9.5437 (7) Å ; b = 9.5349 (6) Å; c = 14.0268 (10) Å; α = 108.943 (1) °; β = 74.154 (1) ° and γ = 119.780 (1) ° as well as 2 formula units per unit cell .
See also
literature
- Andrew M. McDonald, George Y. Chao: Martinite, a new hydrated sodium calcium fluorborosilicate species from Saint-Hilaire, Québec: Description, structure determination and genetic implications , in: The Canadian Mineralogist , Volume 45/5 (October 2007), p . 1281-1292 doi : 10.2113 / gscanmin.45.5.1281
Web links
- Mineral Atlas: Martinite (Wiki)
Individual evidence
- ↑ a b IMA / CNMNC List of Mineral Names - Martinite (PDF 1.8 MB; p. 180)
- ↑ Webmineral - Mart Destinite
- ↑ a b c d e f g h Andrew M. McDonald, George Y. Chao: Martinite, a new hydrated sodium calcium fluorborosilicate species from Saint-Hilaire, Québec: Description, structure determination and genetic implications , in: The Canadian Mineralogist , Volume 45/5 (October 2007), pp. 1281–1292 doi : 10.2113 / gscanmin.45.5.1281
- ^ Mindat - Martinite