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Punkaruaivite
A valid IMA mineral species
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About Punkaruaivite
Pegmatite #71 on Malyi Punkaruaiv Mt.
Pegmatite No. 71, Malyi Punkaruaiv Mountain, Lovozersky District, Murmansk Oblast, Russia
Pegmatite No. 71, Malyi Punkaruaiv Mountain, Lovozersky District, Murmansk Oblast, Russia
Formula:
LiTi2(HSi4O12)(OH)2 · H2O
Colour:
brownish yellow to colorless
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
2.60
Crystal System:
Monoclinic
Name:
Named for Mt. Punkaruaiv, the type locality in the Lovozero massif, Kola Peninsula, Russia.
Related to lintisite, eliseevite; and kukisvumite and manganokukisvumite.
AM-4 family of natural titanosilicates.
AM-4 family of natural titanosilicates.
Unique Identifiers
Mindat ID:
38697
Long-form identifier:
mindat:1:1:38697:9
IMA Classification of Punkaruaivite
Approved
IMA Formula:
LiTi4+2Si4O11(OH)3·H2O
Approval year:
2008
First published:
2010
Type description reference:
Yakovenchuk, V. N., Ivanyuk, G. Y., Pakhomovsky, Y. A., Selivanova, E. A., Men'Shikov, Y. P., Korchak, J. A., Krivovichev, S. V., Spiridonova, D. V., Zalkind, O. A. (2010) Punkaruaivite, LiTi2[Si4O11(OH)]2·H2O, a new mineral species from hydrothermal assemblages, Khibiny and Lovozero alkaline massifs, Kola Peninsula, Russia. The Canadian Mineralogist, 48 (1) 41-50 doi:10.3749/canmin.48.1.41
Classification of Punkaruaivite
9.DB.15
9 : SILICATES (Germanates)
D : Inosilicates
B : Inosilicates with 2-periodic single chains, Si2O6; Pyroxene-related minerals
9 : SILICATES (Germanates)
D : Inosilicates
B : Inosilicates with 2-periodic single chains, Si2O6; Pyroxene-related minerals
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Pka | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Punkaruaivite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Brownish yellow to colorless
Streak:
White
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{100}
{100}
Fracture:
Step-Like
Density:
2.60(5) g/cm3 (Measured) 2.55 g/cm3 (Calculated)
Optical Data of Punkaruaivite
Type:
Biaxial (-)
RI values:
nα = 1.658(2) nβ = 1.696(2) nγ = 1.726(5)
2V:
Measured: 85° (5), Calculated: 82°
Max. Birefringence:
δ = 0.068
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:
none
Pleochroism:
Weak
Comments:
Y light brownish yellow, X brownish yellow
Chemistry of Punkaruaivite
Mindat Formula:
LiTi2(HSi4O12)(OH)2 · H2O
Element Weights:
Crystallography of Punkaruaivite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 26.68 Å, b = 8.75 Å, c = 5.24 Å
β = 91.2°
β = 91.2°
Ratio:
a:b:c = 3.049 : 1 : 0.599
Unit Cell V:
1,223.01 ų (Calculated from Unit Cell)
Z:
4
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 13.3 Å | (100) |
| 6.23 Å | (80) |
| 4.38 Å | (60) |
| 4.16 Å | (40) |
| 3.50 Å | (80) |
| 3.01 Å | (70) |
| 2.81 Å | (70) |
| 2.70 Å | (40) |
Reference:
Yakovenchuk, V. N., Ivanyuk, G. Y., Pakhomovsky, Y. A., Selivanova, E. A., Men'Shikov, Y. P., Korchak, J. A., Krivovichev, S. V., Spiridonova, D. V., Zalkind, O. A. (2010) Punkaruaivite, LiTi2[Si4O11(OH)]2·H2O, a new mineral species from hydrothermal assemblages, Khibiny and Lovozero alkaline massifs, Kola Peninsula, Russia. The Canadian Mineralogist, 48 (1) 41-50 doi:10.3749/canmin.48.1.41
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Marchenko Peak, Kukisvumchorr Mt, Murmansk Oblast, Russia