Skip to main content Accessibility help
×
Home

Ferro-ferri-hornblende from the Traversella mine (Ivrea, Italy): occurrence, mineral description and crystal-chemistry

  • Roberta Oberti (a1), Massimo Boiocchi (a2), Frank C. Hawthorne (a3), Neil A. Ball (a3), Fernando Cámara (a4) (a5), Renato Pagano (a6) and Adriana Pagano (a6)...

Abstract

Ferro-ferri-hornblende is a new member of the amphibole supergroup (IMA-CNMNC 2015-054). It has been found in a rock specimen from the historical collection of Leandro De Magistris, which was collected at the Traversella mine (Val Chiusella, Ivrea, Piemonte, Italy). The specimen was catalogued as ‘speziaite', and contains a wide range of amphibole compositions from tremolite/actinolite to magnesio-hastingsite. The end-member formula of ferro-ferri-hornblende is ABCa2 c(Fe+Fe3+)T(Si7Al) O22 W(OH)2 , which requires SiO2 43.41, Al2O3 5.26, FeO 29.66, Fe2O3 8.24 CaO 11.57, H2O 1.86, total 100.00 wt.%. The empirical formula derived from electron microprobe analysis and single-crystal structure refinement for the holotype crystal is A(Na0.10K0.13) Σ=0.23 B(Ca 1.93Na0.07)Σ=2.00 C(Mg1.16Fe2+ 3.21Mn0.O6 Fe3+ 0.45 Al0.12Ti 0.01)Σ=5.01 T(Si7.26Al0. 74)Σ=8.00 O22 W(OH1.89F0.01C10.10)Σ=2.00- Ferro-ferri-hornblende is biaxial (-), with α = 1.697(2), P = 1 .722(5), γ = 1.726(5) and 2V (meas.) = 35.7(1.4)°, 2V (calc.) = 43.1°. The unit-cell parameters are a = 9.9307(5), b = 18.2232(10), c = 5.3190(3) Å, β = 104.857(1)°, V= 930.40 (9) Å3, Z= 2, space group C2/m. The a:b:c ratio is 0.545:1:0.292. The strongest eight reflections in the powder X-ray pattern [d values (in Å), I, (hkl)] are: 8.493, 100, (110); 2.728, 69, (151); 3.151, 47, (310); 2.555, 37, (); 2.615, 32, (061); 2.359, 28, (); 3.406, 26, (131); 2.180, 25, (261). Type material is deposited in the collections of the Museo di Mineralogia, Dipartimento di Scienze della Terra e dell'Ambiente, Università di Pavia, under the catalogue number 2015-01. Sample M/U15285 from the historical collection of Luigi Colomba, presently at the Museo Regionale di Scienze Naturali di Torino, was also checked, and the presence of ferro-ferri-hornblende was confirmed.

Copyright

Corresponding author

References

Hide All
Bartelmehs, K.L., Bloss, F.D., Downs, R.T. and Birch, J.B. (1992) EXCALIBR II. Zeitschrift für Kristallographie, 199, 185196.
Bruker (2003) SAINT Software Reference Manual. Version 6. Bruker AXS Inc., Madison, Wisconsin, USA.
Colomba, L. (1914) Speziaite, nuovo anfibolo di Traversella, Atti della R. Accad. delle scienze di Torino, XLIX, 625634.
Deer, W.A., Howie, R.A. and Zussman, J. (1997) Rock-Forming minerals. Volume 2B. Double-Chain Silicates,2nd edition, Geological Society of London, London, Bath, 764 pp.
Hawthorne, F.C. and Oberti, R. (2007) Amphiboles: crystal chemistry. Pp. 1—54 in: Amphiboles: Crystal Chemistry, Occurrence andHealth Issues . (F.C. Hawthorne,R.Oberti,G.Della Ventura and A.Mottana,editors).ReviewsinMineralogy.Geochemistry, 67, Mineralogical Society of America and the Geochemical Society, Chantilly, Virginia, USA.
Hawthorne, F.C., Oberti, R., Harlow, G.E., Maresch, W.V., Martin, R.F., Schumacher, J.C. and Welch, M.D. (2012) Nomenclature of the amphibole supergroup. American Mineralogist, 97, 2031–2048.
Leake, B.E.(1978)Nomenclature of amphiboles. American Mineralogist, 63, 10231052.
Oberti, R., Ungaretti, L., Cannillo, E. and Hawthorne, E. (1993) The mechanism ofCl incorporation in amphibole. American Mineralogist, 78, 746—752.
Oberti, R., Hawthorne, EC, Cannillo, E. and Camara, E (2007) Long-range order in amphiboles. Pp. 125—171 in: Amphiboles: Crystal Chemistry, Occurrence and Health Issue. (F.C. Hawthorne, R. Oberti, G. Della Ventura and A. Mottana, editors). Reviews in Mineralogy & Geochemistry, 67, Mineralogical Society of America and the Geochemical Society, Chantilly, Virginia, USA.
Oberti, R., Boiocchi, M., Hawthorne, EC, Ball, N.A. and Chiappino, L. (2016) Magnesio-ferri-fluoro-hornblende from Portoscuso, Sardinia, Italy: description of a newly approved member of the amphibole supergroup. Mineralogical Magazine, 80, 269275.
Sheldrick, G.M. (1996) SADABS Siemens Area Detector Absorption Correction Program. University of Göttingen, Göttingen, Germany.

Keywords

Type Description Title
UNKNOWN
Supplementary materials

Oberti et al. supplementary material
Crystallographic information file 1

 Unknown (167 KB)
167 KB
UNKNOWN
Supplementary materials

Oberti et al. supplementary material
Crystallographic information file 2

 Unknown (30 KB)
30 KB

Ferro-ferri-hornblende from the Traversella mine (Ivrea, Italy): occurrence, mineral description and crystal-chemistry

  • Roberta Oberti (a1), Massimo Boiocchi (a2), Frank C. Hawthorne (a3), Neil A. Ball (a3), Fernando Cámara (a4) (a5), Renato Pagano (a6) and Adriana Pagano (a6)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed