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Berndtite
A valid IMA mineral species
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About Berndtite
Fritz Berndt
Formula:
SnS2
Colour:
Yellow-brown
Lustre:
Resinous
Hardness:
1 - 2
Specific Gravity:
4.5
Crystal System:
Trigonal
Member of:
Name:
For Dr. Fritz Berndt, born 14 November 1916, German Mineralogist at Corporation Minera de Bolivia, Oruro.
There are two polytypes, -2T and -4H.
Not isostructural with is chemical Ge analogue, radvaniceite (not a true analogy).
Not isostructural with is chemical Ge analogue, radvaniceite (not a true analogy).
Unique Identifiers
Mindat ID:
637
Long-form identifier:
mindat:1:1:637:4
Similar Names
| Brandtite | A valid IMA mineral species - grandfathered | Ca2Mn2+(AsO4)2 · 2H2O |
IMA Classification of Berndtite
Approved
IMA Formula:
Sn4+S2-2
First published:
1964
Classification of Berndtite
2.EA.20
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
E : Metal Sulfides, M: S <= 1:2
A : M:S = 1:2 - With Cu, Ag, Au
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
E : Metal Sulfides, M: S <= 1:2
A : M:S = 1:2 - With Cu, Ag, Au
2.12.14.5
2 : SULFIDES
12 : AmBnXp, with (m+n):p = 1:2
2 : SULFIDES
12 : AmBnXp, with (m+n):p = 1:2
3.6.3
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
6 : Sulphides etc. of Sb and Pb
3 : Sulphides, Selenides, Tellurides, Arsenides and Bismuthides (except the arsenides, antimonides and bismuthides of Cu, Ag and Au, which are included in Section 1)
6 : Sulphides etc. of Sb and Pb
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 |
|---|---|---|
| Bti | 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 Berndtite
Resinous
Transparency:
Transparent, Translucent
Colour:
Yellow-brown
Streak:
Golden yellow
Hardness:
1 - 2 on Mohs scale
Cleavage:
Distinct/Good
On {0001}
On {0001}
Density:
4.5 g/cm3 (Measured) 4.55 g/cm3 (Calculated)
Comment:
Measured on synthetic material
Optical Data of Berndtite
Type:
Uniaxial (-)
RI values:
nω = 1.93 nε = 1.705
Max. Birefringence:
δ = 0.225
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 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.
Anisotropism:
Dark greenish gray
Colour in reflected light:
Gray
Internal Reflections:
Intense brownish to orange-yellow
Pleochroism:
Strong
Chemistry of Berndtite
Mindat Formula:
SnS2
Elements listed:
Crystallography of Berndtite
Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
P3m1
Setting:
P3m1
Cell Parameters:
a = 3.639 Å, c = 5.868 Å
Ratio:
a:c = 1 : 1.613
Unit Cell V:
67.30 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Tabular hexagonal crystals.
Comment:
On C6 polymorph
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
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Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
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View
CIF File Best | x | y | z | a | b | c
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Rotation
Stop | Start
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Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0000625 | Berndtite | Hazen R M, Finger L W (1978) The crystal structures and compressibilities of layer minerals at high pressure. I. SnS2, berndtite American Mineralogist 63 289-292 |  | 1978 | 0 | 293 | |
| 0011799 | Berndtite | Wyckoff R W G (1963) Second edition. Interscience Publishers, New York, New York Crystal Structures 1 239-444 | 1963 | 0 | 293 | ||
| 0018172 | Berndtite | Oftedal I (1926) Die Kristallstruktur von Sn S2 _cod_database_code 1011330 Norsk Geologisk Tidsskrift 9 225-233 | 1926 | 0 | 293 | ||
| 0000626 | Berndtite | Hazen R M, Finger L W (1978) The crystal structures and compressibilities of layer minerals at high pressure. I. SnS2, berndtite American Mineralogist 63 289-292 | | 1978 | 1.2 | 293 | |
| 0000627 | Berndtite | Hazen R M, Finger L W (1978) The crystal structures and compressibilities of layer minerals at high pressure. I. SnS2, berndtite American Mineralogist 63 289-292 | | 1978 | 3 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.89 Å | (100) |
| 2.784 Å | (55) |
| 3.162 Å | (30) |
| 1.824 Å | (30) |
| 2.155 Å | (25) |
| 1.743 Å | (20) |
| 1.669 Å | (8) |
Comments:
Synthetic
Type Occurrence of Berndtite
General Appearance of Type Material:
Very fine inclusions in pyrite which has replaced stannite. Tabular habit .
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, numbers 114486 and C5354A.
Geological Setting of Type Material:
Secondary mineral in a tin deposit.
Associated Minerals at Type Locality:
Other Language Names for Berndtite
Relationship of Berndtite to other Species
Member of:
Other Members of Melonite Group:
| Kitkaite | NiTeSe | Trig. 3m(32/m) : P3m1 |
| Melonite | NiTe2 | Trig. 3m(32/m) : P3m1 |
| Merenskyite | PdTe2 | Trig. 3m : P3m1 |
| Moncheite | Pt(Te,Bi)2 | Trig. 3m(32/m) : P3m1 |
| Shuangfengite | IrTe2 | Trig. 3m : P3m1 |
| Sudovikovite | PtSe2 | Trig. 3m(32/m) : P3m1 |
Common Associates
Associations Based on Photo Data:
| 1 photo of Berndtite associated with Herzenbergite | SnS |
| 1 photo of Berndtite associated with Ottemannite | Sn2S3 |
| 1 photo of Berndtite associated with Tschermigite | (NH4)Al(SO4)2 · 12H2O |
Related Minerals - Strunz-mindat Grouping
| 2.EA. | Radvaniceite | GeS2 |
| 2.EA. | Zavyalovite | Ag2TeS3 |
| 2.EA.05 | Sylvanite | AgAuTe4 |
| 2.EA.10 | Calaverite | AuTe2 |
| 2.EA.15 | Kostovite | CuAuTe4 |
| 2.EA.15 | Krennerite | Au3AgTe8 |
| 2.EA.20 | Melonite | NiTe2 |
| 2.EA.20 | Merenskyite | PdTe2 |
| 2.EA.20 | Ognitite | NiBiTe |
| 2.EA.20 | Shuangfengite | IrTe2 |
| 2.EA.20 | Sudovikovite | PtSe2 |
| 2.EA.20 | Kitkaite | NiTeSe |
| 2.EA.20 | Moncheite | Pt(Te,Bi)2 |
| 2.EA.25 | Verbeekite | PdSe2 |
| 2.EA.30 | Drysdallite | MoSe2 |
| 2.EA.30 | Jordisite | MoS2 |
| 2.EA.30 | Molybdenite | MoS2 |
| 2.EA.30 | Tungstenite | WS2 |
| 2.EA.40 | Pampaloite | AuSbTe |
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 Berndtite
mindat.org URL:
https://www.mindat.org/min-637.html
Please feel free to link to this page.
Please feel free to link to this page.
Lichtenberg Absetzer dump, Kauern, Greiz District, Thuringia, Germany