Tuhualite
This page is currently not sponsored. Click here to sponsor this page.
About Tuhualite
Classification of Tuhualite
Approved, 'Grandfathered' (first described prior to 1959)
8/F.30-20
9.DN.05
9 : SILICATES (Germanates)
D : Inosilicates
N : Inosilicates with 6-periodic double chains
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
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
16 : Silicates Containing Aluminum and other Metals
18 : Aluminosilicates of Fe and alkalis
Physical Properties of Tuhualite
Colour:
Dark blue to black
Tenacity:
Very brittle
Cleavage:
Distinct/Good
Three good on (001), (010), (100)
Three good on (001), (010), (100)
Density:
2.89(2) g/cm3 (Measured)
Optical Data of Tuhualite
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.
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 Tuhualite
Formula:
NaFe2+Fe3+Si6O15
Na may be replaced by minor K.
Na may be replaced by minor K.
Elements listed:
Common Impurities:
Ti,Zr,Al,Mn,Mg,Ca,F,Cl,H2O
Crystallography of Tuhualite
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 Tuhualite
Geological Setting of Type Material:
in rhyolites
Associated Minerals at Type Locality:
Other Language Names for Tuhualite
Relationship of Tuhualite to other Species
Common Associates
Associated Minerals Based on Photo Data:
1 photo of Tuhualite associated with Sogdianite | K(□,Na)2Li3(Zr,Fe,Ti)2[Si12O30] |
1 photo of Tuhualite associated with Polylithionite | KLi2Al(Si4O10)(F,OH)2 |
1 photo of Tuhualite associated with Quartz | SiO2 |
1 photo of Tuhualite associated with Aegirine | NaFe3+Si2O6 |
Related Minerals - Nickel-Strunz Grouping
9.DN.05 | Emeleusite | Li2Na4Fe2Si12O30 | Orth. |
9.DN.05 | Zektzerite | LiNaZrSi6O15 | Orth. |
9.DN.10 | Semenovite-(Ce) | Na8Ca2FeBe6Ce2Si14O40(OH)4F4 | Orth. mmm (2/m 2/m 2/m) |
9.DN.15 | Ashcroftine-(Y) | K5Na5(Y,Ca)12Si28O70(OH)2(CO3)8 · 8H2O | Tet. 4/mmm (4/m 2/m 2/m) : I4/mmm |
Related Minerals - Dana Grouping (8th Ed.)
66.3.4.2 | Zektzerite | LiNaZrSi6O15 | Orth. |
66.3.4.3 | Emeleusite | Li2Na4Fe2Si12O30 | Orth. |
Related Minerals - Hey's Chemical Index of Minerals Grouping
16.18.1 | Nontronite | Na0.3Fe2((Si,Al)4O10)(OH)2 · nH2O | Mon. |
16.18.2 | Ferro-glaucophane | ◻[Na2][Fe2+3Al2]Si8O22(OH)2 | Mon. |
16.18.4 | Annite | KFe2+3(AlSi3O10)(OH)2 | Mon. 2/m : B2/m |
16.18.5 | Siderophyllite | KFe2+2Al(Al2Si2O10)(OH)2 | Mon. |
Other Information
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 Tuhualite
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.
Merlino, S., Biagioni, C. (2018): Tuhualite revisited: new crystal data and structure refinements on specimens from two localities. Periodico die Mineralogia 87, 257-267.
Internet Links for Tuhualite
mindat.org URL:
https://www.mindat.org/min-4045.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
Localities for Tuhualite
Locality List




All localities listed without proper references should be considered as questionable.
Italy | |
| Bagiński, B., Macdonald, R., White, J. C., & Jeżak, L. (2018). Tuhualite in a peralkaline rhyolitic ignimbrite from Pantelleria, Italy. European Journal of Mineralogy. |
Mongolia | |
| 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) | |
| 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 | |
| L.A. Pautov data |
Mayor Island, Bay of Plenty Region, New Zealand