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Berezanskite
A valid IMA mineral species
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About Berezanskite
Formula:
K◻2Ti2Li3[Si12O30]
Colour:
White
Lustre:
Vitreous, Pearly
Hardness:
2½ - 3
Specific Gravity:
2.66
Crystal System:
Hexagonal
Member of:
Name:
Named after Anatolyi Vladimirovich Berezansky (Анатолий Владимирович Березанский) (b. 1948), who mapped the geology of remote areas of the Turkestan-Alai range, in Tajikistan.
Isostructural with:
The Ti analogue of brannockite and sogdianite. Chemically somewhat similar to orlovite. The structure is based on the framework of [T(2)Li3T(1)Si12O30] group, containing, i.a., LiO4 tetrahedra. The A (Ti), B (◻), and C (K) sites are interstitial. The <C-O> distance is in inverse relation to the B site occupancy.
Unique Identifiers
Mindat ID:
6824
Long-form identifier:
mindat:1:1:6824:2
IMA Classification of Berezanskite
Approved
IMA Formula:
KTi4+2(Li3Si12)O30
Approval year:
1996
First published:
1997
Classification of Berezanskite
9.CM.05
9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
9 : SILICATES (Germanates)
C : Cyclosilicates
M : [Si6O18]12- 6-membered double rings (sechser-Doppelringe)
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 |
|---|---|---|
| Bzk | 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 Berezanskite
Vitreous, Pearly
Colour:
White
Streak:
White
Hardness:
2½ - 3 on Mohs scale
Hardness:
VHN20=68.5 kg/mm2 - Vickers
Cleavage:
Perfect
basal cleavage {0001}
basal cleavage {0001}
Density:
2.66(2) g/cm3 (Measured) 2.674 g/cm3 (Calculated)
Optical Data of Berezanskite
Type:
Uniaxial (-)
RI values:
nω = 1.635 nε = 1.63
Max. Birefringence:
δ = 0.005
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:
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 uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Chemistry of Berezanskite
Mindat Formula:
K◻2Ti2Li3[Si12O30]
Element Weights:
Crystallography of Berezanskite
Crystal System:
Hexagonal
Class (H-M):
6/mmm(6/m2/m2/m) - Dihexagonal Dipyramidal
Space Group:
P6/mcc
Cell Parameters:
a = 9.903 Å, c = 14.274 Å
Ratio:
a:c = 1 : 1.441
Unit Cell V:
1211.9 ų
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.15 Å | (40) |
| 4.29 Å | (50) |
| 4.07 Å | (85) |
| 3.57 Å | (80) |
| 3.16 Å | (100) |
| 2.895 Å | (95) |
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 |
Type Occurrence of Berezanskite
General Appearance of Type Material:
Occurs as aggregates, up to 2x3 mm, and as vein-like aggregates to 3x20 mm, consisting of platy grains up to 0.6 mm across.
Place of Conservation of Type Material:
Mining museum of the St. Petersburg Mining Institute, Russia and in the Ilmen Natural Reserve museum, Miass, Russia.
Associated Minerals at Type Locality:
Reference:
Dara-i-Pioz Massif, Districts of Republican Subordination, Tajikistan