Bindheymit ((Pb, Ca) 2-x Sb 2 5+ 6-7 * n H 2 O ) is a mineral of the oxide class, the pyrochlore group of the stibiconite group . Named after the German chemist Johann Jacob Bindheim , who first analyzed this mineral from the Nikolaev mine ( Nerchinsky District ), although it did not identify antimony in it; antimony was determined by repeated analysis of Pfaff .
| Bindheymit | |
|---|---|
| Formula | (Pb, Ca) 2-x Sb 2 5+ 6-7 * n H 2 O ' |
| Molecular mass | 770.15 |
| Impurity | As, Bi, Ca, Fe, Na |
| Year of discovery | 1800 |
| IMA status | Valid |
| Systematics by IMA ( Mills et al., 2009 ) | |
| Class | Oxides and hydroxides |
| Subclass | Complex oxides |
| Overgroup | Pyrochlor |
| Group | Stibiconite |
| Physical properties | |
| Colour | Yellow, yellowish green, green, brown, reddish brown, gray, white |
| Color features | White, yellowish white |
| Shine | Pitch |
| Transparency | Opaque to translucent |
| Hardness | 4β4.5 |
| Kink | Crayfish |
| Crystallographic properties | |
| Dot group | m3m |
| Space group | Fd3m |
| Syngony | cubic |
| Cell parameters | 1.039-1.05 nm |
| The number of formula units (Z) | eight |
| Optical properties | |
| Optical type | Isotropic |
| Refractive index | 1.83β1.93 |
| Optical relief | Very tall |
| Reflected color | Gray |
| Internal reflexes | Gray, yellowish-brown |
Synonyms: Stibiogalenite, blainerite, moffrasite, Blumit, pfaffit, antimony-lead spar, icholite.
Content
Characteristic selections
Earthy or dense accumulations, often opal, sometimes crusts, nodules and kidney-like aggregates with concentric layering [1] .
Mineral Characteristics
Crystal structure and morphology
Cubic syngony . Spatial group - Fd3m. Cell parameters a 0 from 1.039 to 1.05 nm ; low values ββof a 0 are inherent to bindheimite, in which Pb is partially replaced by Ca. Artificial Pb 2 Sb 2 O 7 has aa 0 = 1.068 nm, Ca 2 Sb 2 O 7 - 1.03 nm; Z = 8. Pyrochlore type structure , isostructural with stibiconite [1] .
Physical Properties
Cleavage is not observed. The break is conchoidal. Hardness 4-4.5. The specific weight is 4.6β5.6. Color is yellow, yellowish green, green, brown, reddish brown, gray, white. The glitter is pitch, the earthy differences are dim. Opaque to translucent [1] .
Microscopic characteristics
In thin sections in transmitted light, yellow or brownish in different shades. Mostly isotropic, sometimes anomalously anisotropic. n = 1.83-1.93. In reflected light gray. The reflectivity is 9%. Internal reflexes are gray, yellowish-brown [1] .
Chemical composition and properties
The composition of bandhymita is not constant, Ca can partially replace Pb . There are varieties of intermediate composition between bandgeimite and Pb-free hydromereitis . Ag impurities (replaces Pb) and Bi are noted. The water content varies widely. OH groups are not firmly established. When processing NHO 3, bandgeimite decomposes with the release of antimony oxide ; HCl precipitates as a result of the action of HCl . In a closed tube, when heated, it emits water and darkens. Before the soldering tube on the coal gives a metal bead, with a longer exposure to coal is covered with a coating containing oxides of antimony and lead [2] .
Finding
A common mineral is the oxidation zones of deposits in which the hypogenic minerals of lead and antimony are found, mainly boulangerite , jamsonite , zincite , buoroinite . Bindheimite sometimes forms pseudomorphs of these minerals, as well as of tetrahedrite , galena, and mimetesite . Mostly bindehymit is closely associated with various secondary minerals of antimony and lead, sometimes with carbonates and limonite , and often forms mixtures with these minerals. In Russia, it was discovered in a number of fields in Transbaikalia as a product of the change of bulanzherite (district of Nerchinsk and Ekaterininsky mine ), mimetesite (Ekaterininsky mine); accompanied by chrysocolla , skorodite , limonite and other hypergene minerals. The formation of bindheimit on faded ore and galena is noted for the Grace Mine in the Urals. In Oberceiring ( Austria ), the formation of bandhymit is associated with a change in burnonite . In Camerata-Cornello and in Gorno ( Italy ), bandgate is associated with fluorite and various carbonates. In the USA, in Blind Springhill ( California ) in oxidized galena-tetrahedrite ores, bindheimet is observed in association with anglesite , cerussite, and other secondary lead minerals. As a product of Jamsonite oxidation, Bindheimet is installed in a number of places in Nevada ; at the mine of Montezum, it forms large living aggregates, accompanied by perussite and gypsum . Characterized for oxidized ores in Coeur d'Alen ( Idaho , USA ). In Zap. Australia is famous in Gorge Harbor in association with cerussite , anglesite , kaolinite . In addition, it is observed north of Mount Isa ( pieces of Queensland , Australia ) in the form of crusts in small cracks and voids, accompanied by malachite and azurite [2] .
Artificial Reception
An anhydrous analog of bindhumite (with a pyrochlore structure) of composition Pb 2 Sb 2 O 7 was obtained .
Varieties
Ag-containing - corongwit . Earthy powdered, sometimes not clear-lamellar. Hardness 2.5-3. The specific gravity is 5.5. The color of the outer part of the clusters is grayish-yellow, the inner one is darker, with a weak resinous luster. Met in the mines of the Corongo area ( Ankas , Peru ) [2] .
Literature
Chukhrov F. V .. Bonstedt-Kupletskaya. E. M. Minerals. Directory. Issue 3. Complex oxides, titanates, niobates, tantalates, antimonates, hydroxides .. - Moscow: Nauka, 1967. - p. 135-136. - 676 ββs.
Notes
- β 1 2 3 4 Chukhrov, 1967 , p. 135.
- β 1 2 3 Chukhrov, 1967 , p. 136.