Ferri-clinoholmquistite, Li-2(Fe2+,Mg)(3)Fe23+Si8O22(OH)(2), a new Li-B clinoamphibole from the Pedriza Massif, Sierra de Guadarrama, Spanish central system. Caballero, J. M., Monge, A., La Iglesia, A., & Tornos, F. American Mineralogist, 83(1-2):167–171, February, 1998. WOS:000071416100018
doi  abstract   bibtex   
Ferri-clinoholmquistite is a new amphibole species from episyenites in the East Pedriza Massif (Central System, Spain), where it is associated to albite, augite-aegirine, titanite, andradite, magnetite, and apatite. It is black, vitreous, translucent, non-fluorescent, and brittle. It shows gray streak, H(Mohs) = 6, splintery fracture, perfect \110\ cleavage, (001) parting, D-meas = 3.19, and D-cal = 3.25. Crystals are prismatic, elongated on [001]. In plane-polarized light, it is strongly pleochroic: X = yellow green, Y = indigo blue, Z = green blue, with absorption X \textless Y less than or equal to Z; Z = b, Y - c = 10(2)degrees, X - a similar to -2 degrees (in beta obtuse). Ferri-clinoholmquistite is biaxial positive, alpha = 1.699(2), beta = 1.703(2), gamma = 1.708(2), 2V(z)(meas) = 72(7), 2V(z)(calc) = 84(6), r \textless nu. It is monoclinic, space group C2/ m, a = 9.472(4), b = 17.844(6), c = 5.276(6) Angstrom, beta = 101.97(9)degrees, V = 872(1) Angstrom(3), Z = 2. X-ray powder-diffraction pattern data were determined. Analysis by a combination of electron microprobe and flame photometry gives the following formula, calculated assuming OH + F = 2 and T sites fully occupied by Si: (A)(Na0.43K0.03)(B)(Li1.66Na0.30Ca0.04)(C)(Fe-1.54(3+) Fe1.352+Mg1.21Li0.49Al0.20Ti0.124+ Mn-0.07(2+) Zn-0.02)(T)(Si-8)O-22 (OH1.58F0.42). From crystallographic refinements the M4 site is split, implying ordering of Li and Na, and within the A cavity, Na occupies the Am position.
@article{caballero_ferri-clinoholmquistite_1998,
	title = {Ferri-clinoholmquistite, {Li}-2({Fe2}+,{Mg})(3){Fe23}+{Si8O22}({OH})(2), a new {Li}-{B} clinoamphibole from the {Pedriza} {Massif}, {Sierra} de {Guadarrama}, {Spanish} central system},
	volume = {83},
	issn = {0003-004X},
	doi = {10/ghkrhh},
	abstract = {Ferri-clinoholmquistite is a new amphibole species from episyenites in the East Pedriza Massif (Central System, Spain), where it is associated to albite, augite-aegirine, titanite, andradite, magnetite, and apatite. It is black, vitreous, translucent, non-fluorescent, and brittle. It shows gray streak, H(Mohs) = 6, splintery fracture, perfect \{110\} cleavage, (001) parting, D-meas = 3.19, and D-cal = 3.25. Crystals are prismatic, elongated on [001]. In plane-polarized light, it is strongly pleochroic: X = yellow green, Y = indigo blue, Z = green blue, with absorption X {\textless} Y less than or equal to Z; Z = b, Y - c = 10(2)degrees, X - a similar to -2 degrees (in beta obtuse). Ferri-clinoholmquistite is biaxial positive, alpha = 1.699(2), beta = 1.703(2), gamma = 1.708(2), 2V(z)(meas) = 72(7), 2V(z)(calc) = 84(6), r {\textless} nu. It is monoclinic, space group C2/ m, a = 9.472(4), b = 17.844(6), c = 5.276(6) Angstrom, beta = 101.97(9)degrees, V = 872(1) Angstrom(3), Z = 2. X-ray powder-diffraction pattern data were determined. Analysis by a combination of electron microprobe and flame photometry gives the following formula, calculated assuming OH + F = 2 and T sites fully occupied by Si: (A)(Na0.43K0.03)(B)(Li1.66Na0.30Ca0.04)(C)(Fe-1.54(3+) Fe1.352+Mg1.21Li0.49Al0.20Ti0.124+ Mn-0.07(2+) Zn-0.02)(T)(Si-8)O-22 (OH1.58F0.42). From crystallographic refinements the M4 site is split, implying ordering of Li and Na, and within the A cavity, Na occupies the Am position.},
	language = {English},
	number = {1-2},
	journal = {American Mineralogist},
	author = {Caballero, J. M. and Monge, A. and La Iglesia, A. and Tornos, F.},
	month = feb,
	year = {1998},
	note = {WOS:000071416100018},
	keywords = {amphiboles, behavior, disorder, richterite},
	pages = {167--171},
}
Downloads: 0