IMA 2016-065 = vondechenite

database, nuove specie, discrediti,
ridefinizioni, classificazioni, ecc.
Rispondi
Avatar utente
Marco E. Ciriotti
Messaggi: 31675
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

IMA 2016-065 = vondechenite

Messaggio da Marco E. Ciriotti » gio 13 ott, 2016 12:26

Informazioni sulla nuova specie sono nella pagina web di mindat.org: http://www.mindat.org/min-39283.html
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Avatar utente
Marco E. Ciriotti
Messaggi: 31675
Iscritto il: ven 25 giu, 2004 11:31
Località: via San Pietro, 55 I-10073 Devesi/Cirié TO - Italy
Contatta:

Re: IMA 2016-065 = vondechenite

Messaggio da Marco E. Ciriotti » gio 22 feb, 2018 10:41

Referenza:
▪ Schlüter, J., Malcherek, T., Pohl, D., Schäfer, C. (2018): Vondechenite, a new hydrous calcium copper chloride hydroxide, from the Bellerberg, East-Eifel volcanic area, Germany. Neues Jahrbuch fur Mineralogie - Abhandlungen: Journal of Mineralogy and Geochemistry, 195, 79-86.

Abstract:
The mineral vondechenite (IMA 2016-065), Cu4CaCl2(OH)8·4H2O, is a blue hydrous calcium copper chloride hydroxide with a new structure type. The translucent mineral has a vitreous lustre, exhibits a pale blue streak and shows a distinct pleochroism. Its crystals form tiny aggregates of platy crystals not exceeding 1 mm in diameter. Isolated imperfect tabular crystals with {010} as the dominant form are smaller. They have a diameter of not more than 0.5 mm and a thickness of less than 25 μm. Vondechenite is not fluorescent and shows a good cleavage on (010). The name vondechenite is for Ernst Heinrich von Dechen a scientific pioneer for the geology of the western part of Germany. Vondechenite is orthorhombic with space group symmetry Cmcm. Cu atoms are arranged in layers with a pseudo-square topology. Ca atoms are disordered with 48 % vacancies, but streaks of diffuse scattering parallel b* might indicate ordered layers of Ca atoms, with no long range order in b* direction. Unit cell parameters determined by X-ray single crystal diffraction are a = 6.653(1) Å, b = 15.034(3) Å, c = 6.611(1) Å, V = 661.3 (2) Å 3 and Z = 2. The calculated density is 2.85 g/cm3. The strongest lines observed in the simulated X-ray powder diffraction pattern are [d in Å/Irel in %] 7.60/100; 2.48/58; 2.52/49; 3.07/39; 1.73/39. Electron microprobe analyses gave (wt.%) CaO 10.44, CuO 58.25, Fe 0.33, Cl 13.31, O = Cl –3.01, H2 Ocalc. 25.14, sum 104.44 wt.% leading to an empirical formula of Ca1.01(Cu3.97Fe0.02)Cl2.03(OH)7.97·3.58H2O based on 5 cations pfu. The simplified formula is Cu4CaCl2(OH)8·4H2O which requires CaO 9.78, CuO 55.50, Cl 12.37 (O ≡ Cl –2.79), H2O 25.14, total 100.00 wt.%. The new mineral was collected in 1993 in the northern part of the Caspar quarry, Bellerberg volcano, East-Eifel volcanic area, Rhineland-Palatinate, Germany. Vondechenite was found in a xenolith of the Bellerberg basalt in a matrix of white ettringite and jennite.
Marco E. Ciriotti

«Things are interesting only in so far as they relate themselves to other things»

Rispondi

Chi c’è in linea

Visitano il forum: Bing [Bot] e 52 ospiti