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Gottlobite ABSTRACT A new member of the Adelite group called Gottlobite was discovered in friedrichroda, Thuringia Germany. Gottlobite was discovered on the dump of an old abandoned mine called Glucksstern which is located at the Gottlob hill in Friedrichroda. Gottlobite occurs in hydrothermal barite veins that cut conglomerate. Gottlobite is usually grown on Hausmannite crystal as free standing crystals or embedded in barite, often intergrown with Vanadian Adelite. It has some unique physical properties which are rear in other new mineral which were discovered recently. The mineral is composed element made of CaMg(VO4,AsO4) OH. COMPOSITION A chemical analysis of gottlobite was performed using two different pieces of equipment.[4] The energy- dispersive (EDX) and the wavelength- dispersive (WDX) X-ray spectrometer. The EDX spectrum revealed major Ca, V, As and O, and traces of Sr as the main element present. Mg could not be detected due to the overlapping of Mg and As lines.[6] Also quantitative analyses was also performed with a CAMECA SX 100 electron microprobe operated at an acceleration voltage of 15kV and a beam current of 10nA with Diopside (Ca, Mg), Celestite(Sr), Rhodinite(Mn).[5] For data reduction program, the CAMECA program PAP was used. [4] A single grain was analyzed at 19 different points. The main components CaO and MgO shows only slight variation, where as the V2O5 and AsO5 contents were found to be variables.[5] The water content was determined by thermal analysis. The thermogravimetric curve shows a weight loss of 5.4% in one step at 540 degree.[9] The composition calculated for gottlobite with the measured lowest and highest vanadium content are (Ca0.93Sr0.03)(Mg0.91Mn0.04Cu0.04)(V0.63As0.37)O4O1.13H1.26.[1] CRYSTAL STRUCTURE Gottlobite belongs to the adelite group of arsenates and vanadates which crystallize in space group P212121.[11] The adelite group structure is closely related to that of descloizite group which is characterized by space group Pnma. The basic structure is also found in silicates Vugnnatite, CaAl(SiO4)OH and Mozartite CaMn(SiO4)(OH).[8] The V/As ratio was a free parameter during structural refinement. Hence, the obtained value, 0.75/0.25 is within the measured V/As.[8] The atoms are regular tetrahedral coordination with a bond length between 1.694(5) and 1.728(4) and angles between 102.8(2) and 114.1(2) in degree. The Ca atom has 8 ligands; the bond to the O1 atom is much shorter (2.294(4)) than the other oxygen (2.453(5)) – (2.674(5)).[9] The edge sharing Ca-O polyhedral form chains along [100].[8] The crystal structure of gottlobite is showed in figure 1

PHYSICAL PROPERTIES Gottlobite has some unique properties which are rarely seen on other minerals. This unique mineral occurs as orange to orange-brown in appearance is isometric to tabular crystal and isometric grains up to 0.5mm in size. [6] Gottlobite has a tabular crystal which shows dominant {010} form. It can also occur in forms such as {110} and {011} sometimes also as {111} and {101}[5]. Its luster is vitreous to adamantine while its diaphaneity, transparent. [4] It has a hardness of 4.5 while in tenacity, Gottlobite is brittle.[6] Have no observable cleavage and it fractures conchoidal to irregular. Density of 3.31 g/cm2 (measure), 3.40g/cm2(calculated).Gottlobite chemical analytical data. Mean of nineteen sets of electron-microprobes: Ca 24.98, SrO 0.92, MgO 17.54, MnO 1.50, CuO 1.44, V2O5 27.47, As2O5 20.32, H2O 5.40,( From thermogravimetric analysis).[4] Which gives a total of 99.57 wt. %.[1] The amount of H2O was established by TGA. Gottlobite has an empirical formula: (Ca0.93Sr0.03)(Mg0.91Mn0.04Cu0.04)(V0.63As0.37)O4O1.08H1.26 (based on 1 V + As), and the simple formula is given as CaMg(VO4,AsO4) OH.[1] The refine crystal structure is R(F) = 0.0446 and Wr(F-2) = 0.085[1]. Gottlobite has a streak which is light brown and have a vitreous to adamantine luster and are transparent in appearance.[2] Both cleavage and twinning was not observed .gottlobite is brittle; its fracture is conchoidal to irregular.[2] When measured sing the float-sing method in a solution of sodium polytungstate, its density was higher than 3.31g/cm3.[3] Due to its paucity and viscosity of the solution, the density could not be measured with sufficient accuracy.[7] The calculated densities for Z = 4 are and 3.41 and 3.58 g/cm3 for the highest and lowest measured Vanadium respectively.[7] The value for the average composition is 3.46 g/cm3. [11] Reference 1.	Basso, R., Lucchetti, G., Zefiro, L. & Palenona, A. (1993) : Mozartite, CaMn(OH)SiO4, a new mineral species from the Cerchiara     mine, northern Apennines, Italy. – Can. Miner. 31: 331-336 2.	Cesbron, F. P., Ginderow, D., Giraud, R., Pelisson, P. & Pillard, F. (1987): La nickkelaustinite 3.	Ca (Ni,Zn)(AsO4)OH: nouvelle espece mineral du district cobalto-nickelifere de Bou. Azzer, Marco. – Miner. 25: 401-407 4.	Credner, H. (1847): Uber das Vorkommen von vanadinsaurem Kupfer-Oxyd und Kupfer-     Manganerz bei Friedrichrode im Thuringer Wald - N. Jb. Miner., Geogn., Geol. U. petref., 1-7 5.	Credner, H. (1848): Pog. Ann. Phys. Chem. 74: 546 (quoted by Hintze 1933). 6.	Giuseppetti, G. & Tadini, C. (1988): the crystal structure of austenite, CaZn(AsO4)(OH), from      Kamareza, Laurion, Greece. –N. Jb. Miner. Mh. 1988: 159-166. 7.	Guillemin, C. (1955): Une nouvelle espece minerale: la vesigniete CuBa(VO4)2(OH). – Compt. Rend. Acad. Sci Paris 240: 2331-2333. 8.	Hintze, C. (1933): Handbuch der Mineralogie, Vol 1, IV. – Walter de Gruyter & Co., Leipzig and Berlin. 9.	Moore. P. B. (1967): Gabrielsonite, PbFe(AsO4)(OH), a new member of the descloizite-pyrobelonite group, from Langban. – Ark. Milner. Geol., Paper 4: 401-405 10.	Qurashi, M. M. & Barnes. W. D. (1988): The structure of minerals of the descloizite and adelite groups. IV. Descloizite and conichalcite (part 2). The structure of conichalcite. – Can. Miner. 7: 561-577 11.	Shelreick, G. (1993): SHELX-93, a program for the crystal structure determination; XEMP. University of Gottingen, Germany.