Ferro-ferri-hornblende explained

Ferro-ferri-hornblende
Category:	Inosilicate Amphibole supergroup
Formula:	☐Ca2(Fe^2+4Fe^3+)(Si7Al)O22(OH)2
Imasymbol:	Ffhbl^[1]
System:	Monoclinic
Class:	Prismatic (2/m) (same H-M symbol)
Symmetry:	C2/m
Unit Cell:	a = 9.93, b = 18.22 c = 5.32 [Å], β = 104.86° (approximated)
References:	^[2]

Ferro-ferri-hornblende is an amphibole-supergroup mineral with the formula ☐Ca₂(Fe²⁺₄Fe³⁺)(Si₇Al)O₂₂(OH)₂. It contains essential vacancy (☐). It was discovered in the Traversella mine, Canavese, Torino, Piedmont, Italy.^[3]

Notes and References

1. Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
2. Web site: Ferro-ferri-hornblende: Ferro-ferri-hornblende mineral information and data . Mindat.org . 2016-03-13.
3. Oberti, R., Boiocchi, M., Hawthorne, F.C., Ball, N.A., Pagano, R., and Pagano, A., 2015. Ferro-ferri-hornblende, IMA 2015-054. CNMNC Newsletter No. 27, October 2015, 1227; Mineralogical Magazine 79, 1229–1236