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Vitimite
A valid IMA mineral species
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About Vitimite
Formula:
Ca6[B14O19](SO4)(OH)14 · 5H2O
Colour:
White
Lustre:
Vitreous, Silky
Hardness:
1½
Specific Gravity:
2.29
Crystal System:
Monoclinic
Name:
For the Vitimskoe plateau, Buryatia, Transbaikal region, Russia, on which the type locality is situated.
This page provides mineralogical data about Vitimite.
Unique Identifiers
Mindat ID:
25601
Long-form identifier:
mindat:1:1:25601:2
IMA Classification of Vitimite
Approved
IMA Formula:
Ca6B14O19(S6+O4)(OH)14·5H2O
Approval year:
2001
First published:
2002
Classification of Vitimite
6.H0.45
6 : BORATES
H : Unclassified borates
0 :
6 : BORATES
H : Unclassified borates
0 :
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 |
|---|---|---|
| Vti | 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 Vitimite
Vitreous, Silky
Transparency:
Transparent
Colour:
White
Streak:
White
Hardness:
1½ on Mohs scale
Tenacity:
Sectile
Cleavage:
None Observed
Fracture:
Fibrous
Density:
2.29(3) g/cm3 (Measured) 2.24(3) g/cm3 (Calculated)
Optical Data of Vitimite
Type:
Biaxial (-)
RI values:
nα = 1.532(3) nβ = 1.537(1) nγ = 1.540(1)
2V:
Measured: 75° (15), Calculated: 75°
Max. Birefringence:
δ = 0.008
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:
None to Very Low
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:
Moderate, r > v
Optical Extinction:
Z ∧ b = 5°.
Solongo B deposit, Ozernoe ore cluster, Yeravninsky District, Buryatia, Russia