Rosasite
Rosasit is a rarely occurring mineral from the mineral class of " carbonates and nitrates ." It crystallizes in the crystal system with the chemical composition (Cu, Zn) 2 [( OH) 2 | CO 3 ] and developed mostly translucent to opaque mineral aggregates with spherical, nierigem and traubigem habitus, consisting of needle-like crystals to fibrous between 0.5 and 1 cm ( " Ojuela Mine", Mexico) consist size. The color of the Rosasits varies between green, blue green and light blue, but the stroke color is always blue-green. On the individual crystal faces shows vitreous luster, the corresponding mineral aggregate, however, as a whole shines with a silky sheen.
Rosasit the minerals chrysocolla and turquoise is very similar in color, but they have a different Mohs hardness. Chrysocolla is a Mohs hardness of 2-4 usually much softer and turquoise with 5-6 harder than Rosasit with Mohs hardness of 4.5.
Etymology and history
Was first discovered in 1908 in the Rosasit " Rosas Mine" at Narcao in the Italian province of Carbonia -Iglesias ( Sardinia). After this type locality, the mineral was named by its first describer D. Lovisato.
The type material of the mineral is in the Muséum national d' histoire naturelle (Natural History Museum, Paris) under registration number 109 327.
Classification
In the now outdated but still in use 8th edition of the mineral classification by Strunz the Rosasit still belonged to the common mineral class of " carbonates, nitrates and borates " and then to the Department of " water clear carbonates with foreign anions ", where he along with Azurite the independent " Azurite- Rosasit series" was formed, which were also associated with more Aurichalcit, Brianyoungit, Georgeit, Glaukosphärit, hydrozincite, Kolwezit, Loseyit, McGuinnessit, malachite, Nullaginit, Pokrovskit, Sclarit and Zinkrosasit.
The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the Rosasit in the new class of " carbonates and nitrates " (the borates now form a separate class ). There he still belongs to the department of " carbonates with other anions, without H2O" ( Anhydrous carbonates with foreign anions). This division is, however, precisely divided according to the dominant in the connection cations, so that the mineral is found according to its composition in the subdivision " with Cu, Co, Ni, Zn, Mg, Mn", where it, along with Chukanovit, Georgeit Glaukosphärit, Kolwezit, malachite, Mcguinnessit, Nullaginit, Pokrovskit, Rosasit and Zincrosasit the " Malachitgruppe " with the system no. 5.BA.10 forms.
The mostly commonly used in English-speaking classification of minerals according to Dana assigns the Rosasit as the old Strunz'sche systematics in the common class of " carbonates, nitrates and borates ", There, however, in the fine already divided the department " carbonates with hydroxyl or halogen ". Here he is named the " Rosasitgruppe " with the system no. 16a.03.01 and the other members Glaukosphärit, Kolwezit, Zinkrosasit and Mcguinnessit within the subdivision " carbonates with hydroxyl or halogen, and the general composition (AB ) 2 ( XO) 3Zq ".
Education and Locations
Rosasit forms as a typical secondary mineral in the oxidation zone of copper and zinc deposits, mostly. In paragenesis with other secondary minerals such as azurite and malachite, among other things, Aurichalcit, cerussite, hemimorphite Hydrozincite, Konichalcit and Smithsonite
Worldwide, Rosasit so far (as of 2010) are detected at around 340 localities. In Germany the mineral in several regions of the Black Forest and the Upper Palatinate Forest, was found by Northern Hesse, the resin of North Rhine -Westphalia, Rhineland- Palatinate and the Saxon Erzgebirge. In Austria, Rosasit found in several regions of Carinthia, Salzburg, Styria and Vorarlberg. In Switzerland, the mineral previously occurred only in Novaggio and in some regions of the canton of Valais.
Other localities are Argentina, Australia, Belgium, Bulgaria, Chile, China, Czech Republic, France, Greece, Iran, Ireland, Italy, Japan, Kazakhstan, Madagascar, Mexico, Namibia, Norway, Poland, Romania, Russia, Slovakia, Slovenia, Spain, South Africa, Tajikistan, Hungary, the United Kingdom ( UK ) and the United States of America (USA).
Is well recognized for its " Ojuela Mine" at Mapimí (Durango ) in Mexico, where spherical aggregates with needle-like crystals Rosasit up to one centimeter size were revealed.
Crystal structure
Rosasit crystallizes in the monoclinic space group P21 / m with lattice parameters a = 9.37 Å; b = 12.12 Å; c = 3.13 Å and 90.1 ° β = 4 and formula units per unit cell.