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Tuhualite

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About TuhualiteHide

Formula:
NaFe2+Fe3+Si6O15
Na may be replaced by minor K.
Colour:
Dark blue to black
Specific Gravity:
2.89
Crystal System:
Orthorhombic
Member of:
Name:
From the Maori "Tuhua" (obsidian), the original name for Mayor Island, New Zealand.

Classification of TuhualiteHide

Approved, 'Grandfathered' (first described prior to 1959)
9.DN.05

9 : SILICATES (Germanates)
D : Inosilicates
N : Inosilicates with 6-periodic double chains
66.3.4.1

66 : INOSILICATES Double-Width,Unbranched Chains,(W=2)
3 : Amphiboles - Ca-Na subgroup
16.18.3

16 : Silicates Containing Aluminum and other Metals
18 : Aluminosilicates of Fe and alkalis

Physical Properties of TuhualiteHide

Colour:
Dark blue to black
Tenacity:
Very brittle
Cleavage:
Distinct/Good
Three good on (001), (010), (100)
Density:
2.89(2) g/cm3 (Measured)    

Optical Data of TuhualiteHide

Type:
Biaxial (+)
RI values:
nα = 1.608 nβ = 1.612 nγ = 1.621
2V:
Measured: 61° to 70°, Calculated: 68°
Max Birefringence:
δ = 0.013
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r < v
Comments:
a = colourless to pale lavender, b = violet, lavender, c = intense purplish-blue

Chemical Properties of TuhualiteHide

Formula:
NaFe2+Fe3+Si6O15

Na may be replaced by minor K.
Common Impurities:
Ti,Zr,Al,Mn,Mg,Ca,F,Cl,H2O

Crystallography of TuhualiteHide

Crystal System:
Orthorhombic
Cell Parameters:
a = 14.31 Å, b = 17.28 Å, c = 10.11 Å
Ratio:
a:b:c = 0.828 : 1 : 0.585
Unit Cell V:
2,499.97 ų (Calculated from Unit Cell)

Type Occurrence of TuhualiteHide

Other Language Names for TuhualiteHide

German:Tuhualit
Spanish:Tuhualita

Relationship of Tuhualite to other SpeciesHide

Member of:
Other Members of this group:
EmeleusiteLi2Na4Fe2Si12O30Orth.
ZektzeriteLiNaZrSi6O15Orth.

Common AssociatesHide

Associated Minerals Based on Photo Data:
Sogdianite1 photo of Tuhualite associated with Sogdianite on mindat.org.
Polylithionite1 photo of Tuhualite associated with Polylithionite on mindat.org.
Quartz1 photo of Tuhualite associated with Quartz on mindat.org.
Aegirine1 photo of Tuhualite associated with Aegirine on mindat.org.

Related Minerals - Nickel-Strunz GroupingHide

9.DN.05EmeleusiteLi2Na4Fe2Si12O30Orth.
9.DN.05ZektzeriteLiNaZrSi6O15Orth.
9.DN.10Semenovite-(Ce)Na8Ca2FeBe6Ce2Si14O40(OH)4F4Orth. mmm (2/m 2/m 2/m)
9.DN.15Ashcroftine-(Y)K5Na5(Y,Ca)12Si28O70(OH)2(CO3)8 · 8H2OTet. 4/mmm (4/m 2/m 2/m) : I4/mmm

Related Minerals - Dana Grouping (8th Ed.)Hide

66.3.4.2ZektzeriteLiNaZrSi6O15Orth.
66.3.4.3EmeleusiteLi2Na4Fe2Si12O30Orth.

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

16.18.1NontroniteNa0.3Fe2((Si,Al)4O10)(OH)2 · nH2OMon.
16.18.2Ferro-glaucophane◻[Na2][Fe2+3Al2]Si8O22(OH)2Mon.
16.18.4AnniteKFe2+3(AlSi3O10)(OH)2Mon. 2/m : B2/m
16.18.5SiderophylliteKFe2+2Al(Al2Si2O10)(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.

References for TuhualiteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Marshall, P. (1932) Notes on some volcanic rocks of the North Island of New Zealand. The New Zealand Journal of Science and Technology: 13: 198-202.
Foshag, W.F. (1933) New mineral names. American Mineralogist: 18: 179-180.
Marshall, P. (1937) The mineral tuhualite. Transactions and Proceedings of the New Zealand Institute: 66: 330-336.
Foshag, W.F. (1937) New mineral names. American Mineralogist: 22: 1131-1132.
Fleischer, M. (1956) New mineral names. American Mineralogist: 41: 958-960.
Hutton, C.O. (1956) Re-examination of the mineral tuhualite. Mineralogical Magazine, 31:96–106.
Merlino, S. (1969) Tuhualite crystal structure. Science: 166: 1399-1401.
Taran, M. N., & Rossman, G. R. (2001). Optical spectroscopic study of tuhualite and a re-examination of the beryl, cordierite, and osumilite spectra. American Mineralogist, 86(9), 973-980.

Internet Links for TuhualiteHide

Localities for TuhualiteHide

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
 
  • Sicily
    • Trapani Province
Bagiński, B., Macdonald, R., White, J. C., & Jeżak, L. (2018). Tuhualite in a peralkaline rhyolitic ignimbrite from Pantelleria, Italy. European Journal of Mineralogy.
Mongolia
 
  • Hovd Aimag (Khovd Aimag)
    • Altai Mts
Irina A. Andreeva data; Andreeva, I. A. (2016). Genesis and mechanisms of formation of rare-metal peralkaline granites of the Khaldzan Buregtey massif, Mongolia: Evidence from melt inclusions. Petrology, 24(5), 462-476.
New Zealand (TL)
 
  • North Island
    • Bay of Plenty Region (Te Moana-a-Toi)
New Zealand J.Sci.Techn.(1932) 13, 198-202. Osborne Hutton, C. (1956) Re-Examination of the mineral tuhualite. Mineralogical Magazine 31, 96-106.
NZJGG, 2003, 46: 581-590. NZJGG, 1991, 34: 337-340. NZJGG, 1981, 24: 449-467
NZJGG, 2003, 46: 581-590. NZJGG, 1991, 34: 337-340. NZJGG, 1981, 24: 449-467
NZJGG, 2003, 46: 581-590. NZJGG, 1991, 34: 337-340. NZJGG, 1981, 24: 449-467
Tajikistan
 
  • Region of Republican Subordination
    • Tien Shan Mtn
      • Alai Range (Alayskiy)
L.A. Pautov data
Mineral and/or Locality  
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