Angelsite
| Angelsite | |
|---|---|
 |
|
| General and classification | |
| other names |
|
| chemical formula | Pb [SO 4 ] |
|
Mineral class (and possibly department) |
Sulphates (and relatives), see classification |
|
System no. to Strunz and to Dana |
7.AD.35 ( 8th edition : VI / A.09) 03/28/01/03 |
| Similar minerals | Barite , celestine |
| Crystallographic Data | |
| Crystal system | orthorhombic |
| Crystal class ; symbol | orthorhombic-dipyramidal; 2 / m 2 / m 2 / m |
| Space group | Pnma (No. 62) |
| Lattice parameters | a = 8.48 Å ; b = 5.40 Å; c = 6.96 Å |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 2.5 to 3 |
| Density (g / cm 3 ) | measured: 6.38; calculated: 6.36 |
| Cleavage | good after {100}, clearly after {210}; indistinct after {010} |
| Break ; Tenacity | clamshell; brittle |
| colour | colorless, white, gray, orange, yellow, green, blue, rarely purple |
| Line color | White |
| transparency | transparent to opaque |
| shine | Diamond shine to greasy shine |
| Crystal optics | |
| Refractive indices |
n α = 1.878 n β = 1.883 n γ = 1.895 |
| Birefringence | δ = 0.017 |
| Optical character | biaxial positive |
| Axis angle | 2V = measured: 75 °; calculated: 68 ° |
| Other properties | |
| Chemical behavior | slowly soluble in ENT 3 |
| Special features | yellow fluorescence under UV light |
Anglesit , also under the mining designations Bleivitriol or Vitriolbleierz or chemically as a sulfate of lead (II) known is a rarely occurring minerals from the mineral class " Sulfate ( and related )". It crystallizes in the orthorhombic crystal system with the chemical composition Pb [SO 4 ] and develops mostly well-formed, large-area crystals with a tabular, prismatic or dipyramidal habit , the surfaces of which are often streaked along the c-axis and have a diamond to fat-like sheen . Anglesite can, however, also occur in bulbous, stalactitic, granular or massive mineral aggregates or in coarse crusts wrapped around a core of galena .
Also pseudomorphic of Anglesite after galena or conversions to and from Cerussite are known.
Etymology and history
As early as 1779, Antoine Grimoald Monnet , a French mining inspector general, described in his work Nouveau Systême de Minéralogie a newly discovered mineral that had been found at Parys near Amlwch on the Welsh island of Anglesey as vitriol de plomb (English: sulphate of lead , translated: "Sulphate of lead").
Its name, which is still valid today, Anglesite, was only given to the mineral in 1832 by François Sulpice Beudant (1787–1850), a French mineralogist and physicist who named the mineral Anglesey after its locality .
classification
In the now outdated, but still in use 8th edition of the mineral classification according to Strunz , the angelsite belonged to the mineral class of "sulfates, selenates, tellurates, chromates, molybdates and wolframates" and there to the department of "anhydrous sulfates [SO 4 ] without foreign anions " , where together with barite , celestine and hashemite he created the " barite group" with the system no. VI / A.09 .
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 classifies the angelsite in the category of "sulfates (selenates, etc.) without additional anions, without H 2 O". This is, however, further subdivided according to the size of the cations involved , so that the mineral can be found according to its composition in the sub-section “With only large cations”, where together with barite, celestine and olsacherite, the “ barite group” that still exists the system no. 7.AD.35 forms.
The systematics of minerals according to Dana also assigns the anglesite to the class of "sulfates, chromates, molybdates, selenates, tellurates, selenites, tellurites and sulfites" and there in the "sulfates" category. Here it is together with barite and celestine in the "barite group" with system no. 03/28/01 to be found in the subsection of " Anhydrous acids and sulfates (A 2+ ) XO 4 ".
Crystal structure
Anglesite crystallizes isotypically with barite in the orthorhombic crystal system in the space group Pnma (space group no. 62) with the lattice parameters a = 8.48 Å ; b = 5.40 Å and c = 6.96 Å and 4 formula units per unit cell .
The slightly distorted [SO 4 ] 2- - tetrahedron with sulfur at the center are connected to the 12-fold of oxygen coordinated lead 2+ ions heteropolar connected. In simplified terms, the crystal structure can also be described as a deformed sodium chloride structure in which the sodium ions are replaced by lead ions and the chlorine ions by [SO 4 ] tetrahedra.
properties
Pure angelite is colorless and transparent. However, due to foreign admixtures, it can also be yellowish-white, gray or greenish in color and its translucency decreases accordingly. With a Mohs hardness of 2.5 to 3, Anglesite is still one of the soft minerals and can be scratched with a copper coin , for example .
Its density is depending on the purity of 6.3 to 6.4 g / cc (calculated: 6.36 g / cm³), which is about 50% higher than the density of fro very similar in appearance barite barite. In addition, unlike barite and celestine, Anglesite dissolves in concentrated sulfuric acid and potassium hydroxide .
When exposed to UV light , the mineral sometimes shows a weak, yellowish fluorescence .
Education and Locations
Anglesit formed by oxidation of galena ( galena ), and therefore are found most often in Paragenesis with this and other lead minerals such as Cerussit , Lanarkit , Leadhillit , Massicotit , Mimetesit , Pyromorphit , Wulfenit , but also lead-copper or copper minerals such as Brochantit , Caledonit , Linarite , malachite as well as gypsum and solid sulfur .
Anglesite has so far (as of 2011) been detected at around 2000 sites worldwide. Notable sites due to their particularly beautiful and / or large crystals are above all the Fürstenzeche near Lam in the Upper Palatinate (Bavaria), where emerald green ( Bavarian forest emerald ) and fiery red, clearly formed Anglesite crystals came to light. Up to 10 cm long, yellowish angelsite crystals were found in Touissit in the Moroccan prefecture of Oujda-Angad . Angelsite finds of up to 7.5 cm in length are known from the "Bunker Hill Mine" near Kellogg in Shoshone County (Idaho, USA), and crystals up to 4 cm in size have been found in the " Tsumeb Mine" in Namibia.
In addition to the Fürstenzeche in Bavaria, other German sites include the communities of Schmölz , Röhrnbach , Waldsassen and Schwandorf , which are also located in Bavaria ; many areas of the Black Forest in Baden-Württemberg, Odenwald , Spessart and Taunus in Hesse; several sites in the Harz Mountains in Lower Saxony and Saxony-Anhalt; the Aachener Revier , the Bergisches Land , the Eifel , the Sauerland and Siegerland in North Rhine-Westphalia; Hunsrück , Lahntal and Westerwald in Rhineland-Palatinate; Nalbach in Saarland; the Ore Mountains in Saxony and Gera , Greiz and Wurzbach in Thuringia.
In Austria, Anglesite was found in many areas of Carinthia , on the Schwarzberg in the Türnitz Alps (Lower Austria), in several regions of Salzburg and Styria and in Northern Tyrol .
In Switzerland, the mineral has so far been found in the cantons of Bern , Graubünden , Ticino , Uri , Vaud and Valais .
Other locations are Egypt , Argentina , Australia , Belgium , Bolivia , Brazil , Bulgaria , Chile , China , Eritrea , France , Gabon , Greece , India , Indonesia , Iran , Ireland , Italy , Japan , Canada , the Channel Islands Jersey and Little Sark , Kazakhstan , the Democratic Republic of the Congo , Kosovo , Cuba , Luxembourg , Madagascar , Morocco , Macedonia , Mexico , Mongolia , Namibia , New Caledonia , New Zealand , Norway , Poland , Portugal , Romania , Russia , Zambia , Sweden , Zimbabwe , Slovakia , Slovenia , Spain , South Africa , Czech Republic , Tunisia , Turkey , Ukraine , Hungary , Uzbekistan , the United Kingdom (Great Britain) and the United States of America (USA).
use
Despite his lead content of up to 68.3% Anglesite than lead - ore only of local importance for industrial smelting .
As a gemstone , angelsite is of no importance due to its poor physical properties (hardness, cleavability). Occasionally, however, it is brought into shape by hobby cutters with various smooth or facet cuts and then has a certain lover value among interested collectors as an object for exchange and sale.
See also
literature
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 600 .
- Martin Okrusch, Siegfried Matthes: Mineralogy: An introduction to special mineralogy, petrology and deposit science . 7th edition. Springer Verlag, Berlin, Heidelberg, New York 2005, ISBN 3-540-23812-3 , pp. 69, 70 .
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 137 .
Web links
- Mineral Atlas: Anglesite (Wiki)
- David Barthelmy: Anglesite Mineral Data. In: webmineral.com. Retrieved on May 29, 2020 (English).
- Anglesite search results. In: rruff.info. Database of Raman spectroscopy, X-ray diffraction and chemistry of minerals (RRUFF), accessed on May 29, 2020 .
- American-Mineralogist-Crystal-Structure-Database - Anglesite. In: rruff.geo.arizona.edu. Retrieved on May 29, 2020 (English).
- Michael RW Peters: Anglesit. In: realgems.org. June 23, 2012, accessed on May 29, 2020 (with image examples of rough and cut stones).
Individual evidence
- ↑ a b FS Beudant: Anglesite, plomb sulfaté . In: Traité Élémentaire de Minéralogie . 2nd Edition. Paris 1832, p. 459-460 ( rruff.info [PDF; 90 kB ; accessed on October 4, 2017]).
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 370 .
- ↑ a b c d e f Anglesite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 66 kB ; accessed on October 4, 2017]).
- ^ A b Richard V. Gaines, H. Catherine W. Skinner, Eugene E. Foord, Brian Mason , Abraham Rosenzweig: Dana's New Mineralogy . 8th edition. John Wiley & Sons, New York (et al.) 1997, ISBN 0-471-19310-0 , pp. 575 .
- ↑ a b c d e f Anglesite. In: mindat.org. Hudson Institute of Mineralogy, accessed May 29, 2020 .
- ↑ Parys Mountain Copper Mine Amlwch (English, PDF 79.7 kB; p. 1) ( Memento from March 31, 2010 in the Internet Archive )
- ^ Tom Cotterell: Minerals first discovered in Wales. National Museum of Wales, June 29, 2009; Retrieved October 4, 2017 .
- ^ Walter Schumann: Precious stones and gemstones. All kinds and varieties. 1900 unique pieces . 16th, revised edition. BLV Verlag, Munich 2014, ISBN 978-3-8354-1171-5 , pp. 56, 226 .
- ^ Minerals from the Fürstenzeche mine, Lam, Bavarian Forest. (No longer available online.) In: fuerstenzeche.de. Archived from the original on August 10, 2018 ; accessed on October 4, 2017 .
- ↑ Peter R. Hofmann: Underground Bavaria I: A guide to all show mines, rock cellars and other artificial objects . Books on Demand, Norderstedt 2018, ISBN 978-3-7460-9398-7 , pp. 64 ( limited preview in Google Book search).
- ↑ Find location list for Anglesite at the Mineralienatlas and at Mindat