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Ferro-ferri-hornblende

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Formula:
☐Ca2(Fe2+4Fe3+)(AlSi7O22)(OH)2
Defined as a an amphibole in the magnesiohornblende group of the Calcium subgroup with Fe2+Mg and Fe3+Al in the C position and with (OH) as the dominant anion in the W position
Colour:
Dark greenish
Lustre:
Vitreous
Specific Gravity:
3.362
Crystal System:
Monoclinic
Name:
Named in 1789 by Abraham Gottlieb Werner from an old German term for dark minerals with no ore value and from "blende", meaning to deceive. The prefix ferro-ferri is in alignment with the guidelines in the latest amphibole nomenclature (Hawthorne et al 2012)
The mineral was originally described by Luigi Colomba in 1914 as "speziaite", a name never approved by IMA, and discredited by Leake (1978) as a variety of hornblende. As the type material exhibit intergrowths of ferro-ferri-hornblende and hastingsite and magnesio-hastingsite, "speziaite" should not be considered a synonym of ferri-ferro-hornblende.

The type was defined by Oberti et al. (2016) from a rock specimen (catalogued as "speziaite"), from the historical collection of Leandro De Magistris, which was collected at the Traversella Mine (Val Chiusella, Torino, Piemonte, Italy).


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Classification of Ferro-ferri-hornblendeHide

Approved
Approval Year:
2015
First Published:
2016

Pronounciation of Ferro-ferri-hornblendeHide

Pronounciation:
PlayRecorded byCountry
Jolyon & Katya RalphUnited Kingdom

Physical Properties of Ferro-ferri-hornblendeHide

Vitreous
Transparency:
Transparent
Colour:
Dark greenish
Cleavage:
Perfect
on {110}
Density:
3.362 g/cm3 (Measured)    3.35 g/cm3 (Calculated)

Optical Data of Ferro-ferri-hornblendeHide

Type:
Biaxial (-)
RI values:
nα = 1.000 nβ = 1.000 nγ = 1.000
2V:
Measured: 35.7° , Calculated: 43.1°
Max Birefringence:
δ = 0.000
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Moderate
Pleochroism:
Visible
Comments:
X = medium gold/brown (weakest), Y = dark brown/black (strongest), Z = dark grey (medium)

Chemical Properties of Ferro-ferri-hornblendeHide

Formula:
☐Ca2(Fe2+4Fe3+)(AlSi7O22)(OH)2

Defined as a an amphibole in the magnesiohornblende group of the Calcium subgroup with Fe2+Mg and Fe3+Al in the C position and with (OH) as the dominant anion in the W position
IMA Formula:
◻Ca2(Fe2+4Fe3+)(Si7Al)O22(OH)2
Idealised Formula:
☐{Ca2}{Fe2+4Fe3+}(AlSi7O22)(OH)2

Crystallography of Ferro-ferri-hornblendeHide

Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/m
Setting:
C2/m
Cell Parameters:
a = 9.9307(1) Å, b = 18.223(5) Å, c = 5.3190(3) Å
β = 104.857(1)°
Ratio:
a:b:c = 0.545 : 1 : 0.292
Unit Cell V:
930.38 ų (Calculated from Unit Cell)
Morphology:
As acicular or lamellar crystals

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
8.493(100)
3.406(26)
3.151(47)
2.728(69)
2.615(32)
2.555(37)
2.359(38)
2.180(25)

Type Occurrence of Ferro-ferri-hornblendeHide

General Appearance of Type Material:
The type material consists of aggregates of ferro-ferri-hornblende crystals embedded in a matrix of fibrous to acicular tremolite with minor quartz and calcite (as determined by XRPD) analysis). A significant inter-crystalline variation in the hastingsite
Place of Conservation of Type Material:
Type material is deposited in the collections of the Museo di Mineralogia, Dipartimento di Scienze della Terra e dell’Ambiente, Università di Pavia, catalogue number 2015-01
Associated Minerals at Type Locality:

Synonyms of Ferro-ferri-hornblendeHide

Relationship of Ferro-ferri-hornblende to other SpeciesHide

Other Members of this group:
Ferro-ferri-fluoro-hornblende☐{Ca2}{Fe2+4Fe3+}(AlSi7O22)F2
Ferro-fluoro-hornblende☐Ca2(Fe2+4Al)(AlSi7O22)F2
Ferro-hornblende☐{Ca2}{Fe2+4Al}(AlSi7O22)(OH)2Mon.
Magnesio-ferri-fluoro-hornblende☐{Ca2}{Mg4Fe3+}(AlSi7O22)F2Mon. 2/m : B2/m
Magnesio-ferri-hornblende☐{Ca2}{Mg4Fe3+}(AlSi7O22)(OH)2Mon. 2/m : B2/m
Magnesio-fluoro-hornblende(Na,K)1-xCa2Mg5(Si7Al)O22F2
Magnesio-hornblende☐{Ca2}{Mg4Al}(AlSi7O22)(OH)2Mon.

Other InformationHide

Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
None

References for Ferro-ferri-hornblendeHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Colomba, L. (1914) Speziaite, nuovo anfibolo di Traversella, Atti della R. Accad. delle scienze di 226 Torino, XLIX, 625-634.
Hawthorne, F.C., Oberti, R., Harlow, G.E., Maresch, W.V., Martin, R.F., Schumacher, J.C., Welch, M.D. (2012) Nomenclature of the amphibole supergroup. American Mineralogist: 97: 2031-2048.
Oberti, R., Boiocchi, M., Hawthorne, F.C., Ball, N.A.,Pagano, R., Pagano, A. (2015) Ferro-ferri-hornblende, IMA 2015-054. CNMNC Newsletter No. 27, October 2015, page 1227; Mineralogical Magazine: 79: 1229-1236.
Oberti, R., Boiocchi, M., Hawthorne, F.C., Ball, N.A., Cámara, F., Pagano, R., Pagano, A. (2016): Ferro-ferri-hornblende from the Traversella Mine (Ivrea, Italy): occurrence, mineral description and crystal-chemistry. Mineralogical Magazine: 80: 1233-1242

Internet Links for Ferro-ferri-hornblendeHide

Localities for Ferro-ferri-hornblendeHide

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Italy (TL)
 
  • Piedmont
    • Torino Province
      • Canavese District
        • Chiusella Valley
          • Traversella
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, page 1227; Mineralogical Magazine, 79, 1229-1236.; Oberti, R., Boiocchi, M., Hawthorne, F.C., Ball, N.A., Cámara, F., Pagano, R., Pagano, A. (2016): Ferro-ferri-hornblende from the Traversella Mine (Ivrea, Italy): occurrence, mineral description and crystal-chemistry. Mineralogical Magazine: 80: 1233-1242
Mineral and/or Locality  
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