Dundasite

Dundasit is a mineral from the mineral class of " carbonates and nitrates " (formerly known as carbonates, nitrates and borates ). It crystallizes in the orthorhombic crystal system with the chemical composition PbAl2 [( OH) 2 | CO 3 ] 2 · H2O and developed predominantly spherical to radial- up acicular aggregates in white, yellowish and rarely light green or light blue color.

Etymology and history

Was first found in 1893 in the Dundasit " Adeleit Mine" at Dundas ( Zeehan District ) in Tasmania. The describer William Frederick Petterd (1849-1910), an amateur collector and writer of numerous important lists mineralogy of Tasmania, the mineral is named after its type locality.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the Dundasit belonged to common mineral class of " carbonates, nitrates and borates " and then to the Department of " water -containing carbonates with foreign anions ", where he along with Ankylit ( La ), Ankylit - (Ce), Barstowit, Calcio Ankylit - (Ce), Calcio Ankylit - (Nd), Dresserit, Gysinit - (Nd), Hydrodresserit, Kamphaugit - (Y), Kochsándorit, Montroyalit, Petterdit, Strontiodresserit and Thomasclarkit - (Y), the independent group V/E.08 formed.

The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns to the category of " carbonates and nitrates " ( borates here form a separate class) and there is also in the Department of " water -containing carbonates with foreign anions " ( carbonates with additional anions, with H2O). This division, however, is further divided according to the size of the cations involved, so that the mineral is found according to its composition in the subdivision " with large and medium-sized cations ," where it's the only along with Dresserit, Kochsándorit, Montroyalit, Petterdit and Strontiodresserit " Dresseritgruppe " with the system number. 5.DB.10 forms.

The mostly commonly used in English-speaking classification of minerals according to Dana assigns the Dundasit as the outdated Strunz'sche systematics in the class of " carbonates, nitrates and borates " and there in the department of " 16b carbonates - hydroxyl or halogen" one. Here he is with Dresserit, Strontiodresserit, Petterdit and Kochsándorit in the unnamed group 16b.02.01 within the subdivision " Carbonate - hydroxyl or halogen with (A ) m ( B ) n ( XO3 ) PZQ x (H2O), with (m n ): p = 3:2 find ".

Education and Locations

Dundasit is a typical secondary mineral that forms in the oxidation zone of lead deposits. Usually accompanying minerals Krokoit, azurite and malachite, but also Beudantite, Cerussite, Duftit, gibbsite, Mimetitesit, Plattnerit and pyromorphite.

So far, the mineral was found in the following locations: In addition to its type locality Dundas still at Williams Ford in Tasmania in Australia; Liège in Belgium; Guangxi in the People's Republic of China; Lower Saxony ( resin ), North Rhine -Westphalia (Sauerland, winner of the country), Rhineland -Palatinate ( Nothweiler, Bad Ems, Rhine Breitbach ); Alsace, Aquitaine, Languedoc -Roussillon, Provence -Alpes- Côte d' Azur and Rhône -Alpes in France; Attica in Greece; England, Scotland and Wales in Great Britain; Galway and Tipperary in Ireland; Lombardy, Sardinia, Tuscany and Veneto in Italy; Oshikoto Namibia; on the North Island in New Zealand; Carinthia, Salzburg and Styria in Austria; Moravia in the Czech Republic; Heves county in Hungary; as well as Nevada, New Jersey and New Mexico in the United States.

Crystal structure

Dundasit crystallizes in the orthorhombic crystal system, space group Pbnm with lattice parameters a = 9.08 Å, b = 16.37 Å and c = 5.62 Å and four formula units per unit cell.