Greifensteinite
- IMA 2001-044
- Ca2Be4Fe2 5 ( PO4 ) 6 ( OH) 4.6 H2O
- Ca2 ( Fe2 , Mn) 4- 5Be4 [( OH) 4 | ( PO4 ) 6] · 6H2O
Cross Enste Init is a rarely occurring mineral from the mineral class of " phosphates, arsenates and vanadates ." It crystallizes in the monoclinic crystal system with the idealized chemical composition Ca2Be4Fe2 5 ( PO4 ) 6 ( OH) 4.6 H2O, is thus seen chemically a hydrous calcium beryllium - iron - phosphate with additional hydroxide ions.
Cross Enste Init the iron analogue ( Ca2Mn2 5 Be4 ( PO4 ) 6 ( OH) 4.6 H2O) is to Roscherit and Zanazziit ( Ca2Be4Mg5 ( PO4 ) 6 ( OH) 4.6 H2O).
The mineral is transparent to translucent and developed only small, prismatic crystals of dark olive-green color, which are usually arranged in radialstrahligen aggregates.
Etymology and history
Was first discovered gripping Enste Init to the known as Greifensteine rock formation in Saxon Erzgebirge and described in 2002 by NV Chukanov, S. Moeckel, RK Rastsvetaeva and AE Zadov who named the mineral after its type locality.
The type material of the mineral has been deposited in the Museum of Mineralogy and Geology Dresden.
Classification
In the now outdated but still in use 8th edition of the mineral classification by Strunz the gripping Enste Init belonged to the department of " water -containing phosphates with foreign anions ", where he along with Atencioit, Bearsit, Glucin, Guimarãesit, Moraesit, Roscherit, Ruifranconit, Uralolith, Weinebeneit and Zanazziit the unnamed group VII/D.01 formed.
The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the gripping Enste Init also in the department of " phosphates with additional anions, with H2O". However, this is further divided according to the relative size of the cations involved, so that the mineral is found according to its composition in the subsection " With small (and occasionally larger ) cations " where there along with Atencioit, Footemineit, Guimarãesit, Roscherit, Ruifrancoit and Zanazziit the " Roscheritgruppe " with the system no. 8.DA.10 forms.
The mainly common in English-speaking classification of minerals according to Dana assigns the gripping Enste Init in the class of " phosphates, arsenates and vanadates " and there in the department of " water containing phosphates, etc., with hydroxyl or halogen" one. Here he is with Atencioit, Footemineit, Guimarãesit, Roscherit, Ruifrancoit and Zanazziit in the " Roscheritgruppe " with the system no. 42.07.07 found within the subdivision " water containing phosphates, etc., with hydroxyl or halogen with (AB ) 5 ( XO4 ) 3Zq × x (H2O) ".
Education and Locations
Cross Enste Init forms in miarolithischen cavities of lithium-rich granite pegmatites. Accompanying minerals occur among others albite, apatite, Childrenite, elbaite, Herderite, potassium feldspar, montmorillonite, quartz, and Roscherit Viitaniemiit.
A rare mineral formation Greifenstein could be detected only in a few localities, where so far (as of 2013) are about 20 localities known as. Its type locality Greifenstein is the only known locality in Germany.
In Austria, is also far only one locality known. There, the mineral was in an exploration drift to reduce the lithium mineral spodumene at the back fire discovered in the Alpine Pass wine level (Carinthia ) (see also mining in Carinthia ).
Furthermore gripping Enste Init still occurred at several locations in the river valleys of the Rio Doce and the Rio Jequitinhonha in the Brazilian state of Minas Gerais, in the deposit " Ungursai Ta " on the Irtysh River in East Kazakhstan as well as in several places in the U.S. states of Maine and New Hampshire and in the " Tip Top Mine" to near Custer, South Dakota.
Crystal structure
Cross Enste Init crystallizes in the monoclinic space group C2 / c ( Raumgruppen-Nr. 15) with the lattice parameters a = 15.903 Å; b = 11.885 Å; c = 6.677 Å and β = 94.68 ° and four formula units per unit cell.