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Preobrazhenskite
A valid IMA mineral species - grandfathered
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About Preobrazhenskite
Pavel I. Preobrazhenskii
Formula:
Mg3B11O15(OH)9
Colour:
Colourless, lemon-yellow, dark gray
Lustre:
Vitreous
Hardness:
4½ - 5
Specific Gravity:
2.45 (Calculated)
Crystal System:
Orthorhombic
Name:
Named in honor of Pavel Ivanovich Preobrazhenskii (Павел Иванович Преображенский) (13 January 1874, Demyansk, Novgorod Province, Russian Empire - 10 September 1944, Moscow, USSR), geologist with the Institute of Halurgy, St. Petersburg, and the Institute of Mining and Chemical Stock, Moscow, Russia and professor in the Department of Geology and Mineralogy, Perm University. He was an expert in Russian salt deposits and was a discoverer of the Inder deposit, Kazakhstan.
This page provides mineralogical data about Preobrazhenskite.
Unique Identifiers
Mindat ID:
3280
Long-form identifier:
mindat:1:1:3280:9
IMA Classification of Preobrazhenskite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1956
Classification of Preobrazhenskite
6.GB.15
6 : BORATES
G : Heptaborates and other megaborates
B : Phyllo-nonborates, etc.
6 : BORATES
G : Heptaborates and other megaborates
B : Phyllo-nonborates, etc.
25.7.1.1
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
7 : Nonaborates
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
7 : Nonaborates
9.2.5
9 : Borates
2 : Borates of Be and Mg
9 : Borates
2 : Borates of Be and Mg
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 |
|---|---|---|
| Pbz | 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 Preobrazhenskite
Vitreous
Transparency:
Translucent
Colour:
Colourless, lemon-yellow, dark gray
Streak:
White
Hardness:
4½ - 5 on Mohs scale
Density:
2.45 g/cm3 (Calculated)
Optical Data of Preobrazhenskite
Type:
Biaxial (+)
RI values:
nα = 1.573 - 1.576 nβ = 1.573 - 1.576 nγ = 1.594 - 1.596
Max. Birefringence:
δ = 0.020 - 0.021
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:
Moderate (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.
No measured or calculated 2V is on file for this mineral, so the value used here (0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
relatively strong
Chemistry of Preobrazhenskite
Mindat Formula:
Mg3B11O15(OH)9
Element Weights:
Elements listed:
Crystallography of Preobrazhenskite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pbcm
Setting:
Pbcm
Cell Parameters:
a = 16.291(4) Å, b = 9.181(2) Å, c = 10.571(2) Å
Ratio:
a:b:c = 1.774 : 1 : 1.151
Unit Cell V:
1,581.08 ų (Calculated from Unit Cell)
Z:
4
Morphology:
crystals to 4 cm, in nodules and granular massive.
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0005367 | Preobrazhenskite | Burns P C, Hawthorne F C (1994) Structure and hydrogen bonding in preobrazhenskite, a complex heteropolyhedral borate The Canadian Mineralogist 32 387-396 |  | 1994 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.28 Å | (100) |
| 3.79 Å | (100) |
| 3.230 Å | (90) |
| 3.187 Å | (90) |
| 2.821 Å | (90) |
| 2.769 Å | (90) |
| 2.641 Å | (90) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Type Occurrence of Preobrazhenskite
General Appearance of Type Material:
Nodules in fine-grained halite-polyhalite rock and encloses kaliborite and boracite. In places it has been partially replaced by inyoite.
Place of Conservation of Type Material:
1) Mining Institute, St. Petersburg, Russia, 1497/1–2,5.
2) A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, 57015.
2) A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, 57015.
Associated Minerals at Type Locality:
Other Language Names for Preobrazhenskite
Common Associates
Related Minerals - Strunz-mindat Grouping
| 6.GB.05 | Studenitsite | NaCa2[B9O14(OH)4] · 2H2O |
| 6.GB.10 | Penobsquisite | Ca2Fe2+[B9O13(OH)6]Cl · 4H2O |
| 6.GB.20 | Walkerite | Ca16(Mg,Li,◻)2[B13O17(OH)12]4Cl6 · 28H2O |
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 Preobrazhenskite
mindat.org URL:
https://www.mindat.org/min-3280.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
Inder B deposit and salt dome, Inder District, Atyrau Region, Kazakhstan