Nafertisite
A valid IMA mineral species
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About Nafertisite
Formula:
Na3Fe2+10Ti2(Si6O17)2O2(OH)6F(H2O)2
Colour:
Dark grass-green, bronze-brown
Lustre:
Vitreous, Silky
Hardness:
2 - 3
Specific Gravity:
2.7
Crystal System:
Monoclinic
Name:
Named for the composition, containing sodium (Latin NAtrium), iron (Latin FERrum), TItanium, and SIlicon. The name also acknowledges the close relationship to the similarly named bafertisite.
Type Locality:
Related to caryochroite. Closely related to astrophyllite group.
The structure is based on The HOH layers (H - heteropolyhedral, O - octahedral), that are set in alternation with intermediate (I) blocks along c. The O sheet, ideal composition Fe2+10M, is built of M(1–3) octahedra. The H sheet comprises of nafertisite Si6O17 ribbons (there are 2 such ribbons pfu) and Ti-dominant D octahedra. In the I block, the A, B, C and W sites have the following occupancy (Kukisvumchorr material): (Na1.39K0.61), Na, (□0.92Rb0.06Cs0.02). and [(H2O)1.39□0.61] pfu, respectively. The ideal chemical composition of the I block, general formula A2BCW, Na3(H2O)2 pfu.
The structure is based on The HOH layers (H - heteropolyhedral, O - octahedral), that are set in alternation with intermediate (I) blocks along c. The O sheet, ideal composition Fe2+10M, is built of M(1–3) octahedra. The H sheet comprises of nafertisite Si6O17 ribbons (there are 2 such ribbons pfu) and Ti-dominant D octahedra. In the I block, the A, B, C and W sites have the following occupancy (Kukisvumchorr material): (Na1.39K0.61), Na, (□0.92Rb0.06Cs0.02). and [(H2O)1.39□0.61] pfu, respectively. The ideal chemical composition of the I block, general formula A2BCW, Na3(H2O)2 pfu.
Unique Identifiers
Mindat ID:
7186
Long-form identifier:
mindat:1:1:7186:0
Similar Names
| Bafertisite | A valid IMA mineral species - grandfathered | Ba2Fe42+Ti2(Si2O7)2O2(OH)2F2 |
IMA Classification of Nafertisite
Approved
IMA Formula:
Na3Fe2+10Ti4+2(Si6O17)2O2(OH)6F·2H2O
Approval year:
1994
First published:
1995
Classification of Nafertisite
9.EH.30
9 : SILICATES (Germanates)
E : Phyllosilicates
H : Transitional structures between phyllosilicate and other silicate units
9 : SILICATES (Germanates)
E : Phyllosilicates
H : Transitional structures between phyllosilicate and other silicate units
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Naf | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Naf | Warr (2020) | Warr, L.N. (2020) Recommended abbreviations for the names of clay minerals and associated phases. Clay Minerals, 55, 261–264 doi:10.1180/clm.2020.30 |
Physical Properties of Nafertisite
Vitreous, Silky
Colour:
Dark grass-green, bronze-brown
Hardness:
2 - 3 on Mohs scale
Cleavage:
Perfect
{010} and {001}
{010} and {001}
Fracture:
Fibrous
Density:
2.7(1) g/cm3 (Measured) 2.74 g/cm3 (Calculated)
Optical Data of Nafertisite
Type:
Biaxial (-)
RI values:
nα = 1.627(2) nβ = 1.667(2) nγ = 1.693(2)
2V:
Measured: 75° to 76°, Calculated: 76°
Max. Birefringence:
δ = 0.066
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r > v or r < v
Optical Extinction:
Z ≈ a; Y = b; X ∧ c = 5° in obtuse angle β.
Fibers have positive elongation and straight extinction.
Fibers have positive elongation and straight extinction.
Pleochroism:
Strong
Comments:
X = reddish brown, Y = green, Z = dark green, Z > Y >> X
Comments:
Absorption: Z > Y >> X.
Chemistry of Nafertisite
Mindat Formula:
Na3Fe2+10Ti2(Si6O17)2O2(OH)6F(H2O)2
Element Weights:
Crystallography of Nafertisite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Cell Parameters:
a = 5.358(1) Å, b = 16.204(3) Å, c = 21.976(4) Å
β = 94.91(1)°
β = 94.91(1)°
Ratio:
a:b:c = 0.331 : 1 : 1.356
Unit Cell V:
1901 ų
Morphology:
Fibers are 0.01-0.1 mm thick, bounded by {010} and {001} cleavages, flattened along (001), and elongate [100].
Comment:
A2/m
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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Big Balls | Small Balls | Just Balls | Spacefill
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CIF File Best | x | y | z | a | b | c
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
| ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
|---|---|---|---|---|---|---|---|
| 0006619 | Nafertisite | Ferraris G, Ivaldi G, Khomyakov A P, Soboleva S V, Belluso E, Pavese A (1996) Nafertisite, a layer titanosilicate member of a polysomatic series including mica European Journal of Mineralogy 8 241-249 | 1996 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 13.00 Å | (30) |
| 10.94 Å | (100) |
| 4.44 Å | (15) |
| 2.728 Å | (25) |
| 2.641 Å | (20) |
| 2.547 Å | (15) |
| 2.480 Å | (15) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 22 : Hydration and low-? subsurface aqueous alteration (see also #23) | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Nafertisite
General Appearance of Type Material:
Fine, fibrous (asbestiform) light-green aggregates up 5-10 mm across.
Place of Conservation of Type Material:
Fersman Mineralogical Museum, Moscow, Russia.
Regional Museum of Natural History, Turin, Italy.
Regional Museum of Natural History, Turin, Italy.
Geological Setting of Type Material:
Hyperagpaitic pegmatites. Interstitial to potassium feldspar.
Associated Minerals at Type Locality:
Synonyms of Nafertisite
Other Language Names for Nafertisite
Common Associates
Associations Based on Photo Data:
| 9 photos of Nafertisite associated with Aegirine | NaFe3+Si2O6 |
| 4 photos of Nafertisite associated with Albite | Na(AlSi3O8) |
| 3 photos of Nafertisite associated with Analcime | Na(AlSi2O6) · H2O |
| 2 photos of Nafertisite associated with Astrophyllite | K2NaFe2+7Ti2[Si4O12]2O2(OH)4F |
| 1 photo of Nafertisite associated with Natrolite | Na2Al2Si3O10 · 2H2O |
| 1 photo of Nafertisite associated with Catapleiite | Na2Zr(Si3O9) · 2H2O |
| 1 photo of Nafertisite associated with Calcioancylite-(Ce) | (Ce,Ca,Sr)CO3(OH,H2O) |
| 1 photo of Nafertisite associated with Micheelsenite | (Ca2Y)Al(PO3OH)(CO3)(OH)6 · 12H2O |
Related Minerals - Strunz-mindat Grouping
| 9.EH.05 | Manganoneptunite | KNa2Li(Mn2+)2Ti2[Si4O12]2 |
| 9.EH.05 | Magnesioneptunite | KNa2Li(Mg)2Ti2[Si4O12]2 |
| 9.EH.05 | Neptunite | KNa2Li(Fe2+)2Ti2[Si4O12]2 |
| 9.EH.05 | Watatsumiite | KNa2Li(Mn2+)2V4+2[Si4O12]2 |
| 9.EH.05 | Rotherkopfite | KNa2Fe2+(Fe2+)2(Ti1.5Fe2+0.5)[Si4O12]2 |
| 9.EH.10 | Grumantite | Na(HSi2O5) · H2O |
| 9.EH.15 | Sarcolite | Na4Ca12Al8Si12O46(SiO4,PO4)(OH,H2O)4(CO3,Cl) |
| 9.EH.20 | Ussingite | Na2AlSi3O8OH |
| 9.EH.25 | Telyushenkoite | (Cs,Na,K)Na6[Be2Al3Si15O39]F2 |
| 9.EH.25 | Leifite | (Na,H2O)Na6[Be2Al2(Al,Si)Si15O39]F2 |
| 9.EH.25 | Eirikite | KNa6Be2(Si15Al3)O39F2 |
| 9.EH.35 | Veblenite | KNa(Fe2+5Fe3+4Mn7)Nb4(Si2O7)2(Si8O22)2O6(OH)10(H2O)3 |
Fluorescence of Nafertisite
Not fluorescent
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.
Internet Links for Nafertisite
mindat.org URL:
https://www.mindat.org/min-7186.html
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Please feel free to link to this page.
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References for Nafertisite
Reference List:
Khomyakov, A. P., Ferraris, G., Ivaldi, G., Nechelyustov, G. N., Soboleva, S. V. (1995) Nafertisite Na3(Fe2+,Fe3+)6[Ti2Si12O34](O,OH)7·2H2O, a new mineral with a new type of banded silicate radical. Zapiski Vserossijskogo Mineralogicheskogo Obshchestva, 124 (6) 101-107
Jambor, John L., Grew, Edward S., Roberts, Andrew C. (1996) New mineral names. American Mineralogist, 81. 1513-1518
Ferraris, Giovanni, Ivaldi, Gabriella, Khomyakov, Alexander P., Soboleva, Svetlana V., Belluso, Elena, Pavese, Alessandrο (1996) Nafertisite, a layer titanosilicate member of a polysomatic series including mica. European Journal of Mineralogy, 8 (2) 241-249 doi:10.1127/ejm/8/2/0241
Cámara, Fernando, Sokolova, Elena, Abdu, Yassir A., Hawthorne, Frank C. (2014) Nafertisite, Na3Fe2+10Ti2(Si6O17)2O2(OH)6F(H2O)2, from Mt. Kukisvumchorr, Khibiny alkaline massif, Kola peninsula, Russia: Refinement of the crystal structure and revision of the chemical formula. European Journal of Mineralogy, 26 (5) 689-700 doi:10.1127/0935-1221/2014/0026-2401
Localities for Nafertisite
Showing 3 localities.
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and 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).
All localities listed without proper references should be considered as questionable.
Greenland | |
| Petersen et al. (1999) +1 other reference |
Russia (TL) | |
| Khomyakov et al. (1995) +1 other reference |
| ... |
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Nanna pegmatite, Narsaarsuup Qaava, Igaliku, Kujalleq, Greenland