Potassic-aluminotaramite from Sierra de los Filabres, Spain
Potassic-aluminotaramite from Sierra de los Filabres, Spain (in MSA/GS, ANL short course on amphiboles, Roberta Oberti (editor) and Giancarlo Della Ventura (editor))
European Journal of Mineralogy (December 2008) 20 (6): 1005-1010
- Almeria Spain
- amphibole group
- Andalusia Spain
- chain silicates
- chemical composition
- crystal chemistry
- crystal structure
- electron probe data
- Europe
- formula
- holotypes
- Iberian Peninsula
- new minerals
- optical properties
- paragenesis
- physical properties
- refinement
- Sierra de los Filabres
- silicates
- Southern Europe
- Spain
- unit cell
- X-ray diffraction data
- taramite
- potassic-aluminotaramite
Potassic-aluminotaramite, ideally (super A) K(CaNa) (super B) (Fe (sub 3) (super 2+) Al (sub 2) ) (super C) (Si (sub 6) Al (sub 2) )O (sub 22) (super W) (OH) (sub 2) , has been found in a meta-monzonite rock sampled at Sierra de los Filabres, S.E. Spain; the paragenesis that contains the amphibole is mainly formed by feldspar, quartz, and clinopyroxene. This paper reports a complete mineral description and crystal-structure details for this new taramite end-member that has been recognised by IMA-CNMMC with the vote 2007-015. Holotype potassic-aluminotaramite has the experimental unit formula (super A) (Na (sub 0.34) K (sub 0.66) ) (sub Sigma 1.00) (super B) (Fe (sub 0.01) (super 2+) Na (sub 0.85) Ca (sub 1.14) ) (sub Sigma 2.00) (super C) (Fe (sub 2.80) (super 2+) Mg (sub 0.33) Al (sub 1.26) Fe (sub 0.46) (super 3+) Ti (sub 0.05) Mn (sub 0.10) ) (sub Sigma 5.00) (super T) (Si (sub 6.01) Al (sub 1.99) ) (sub Sigma 8.00) O (sub 22) (super W) (OH (sub 1.96) F (sub 0.03) Cl (sub 0.01) ) (sub Sigma 2.00) ; a = 9.8505(5), b = 18.0075(9), c = 5.3518(3) Aa, beta = 104.775(4), V = 917.9(2) Aa (super 3) ; D (sub calc) = 3.40 g/cm (super 3) . Optics: biaxial (-); alpha 1.686(1), beta 1.703(3), gamma 1.706(3) (lambda = 589 nm). The ten strongest reflections in the X-ray powder pattern [d values (in Aa), I, (hkl)] are: 8.420, 100, (110); 2.714, 75.03, (151); 2.565, 59.62, (-202); 3.127, 52.54, (310); 2.596, 49.03, (061); 3.400, 37.92, [(131) (041)]; 2.166, 33.71, [(261) (-332)]; 2.340, 32.38, (-351); 2.956, 24.79, (221); 2.297, 24.57, [(-171) (-312)].
