Bernardite
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About Bernardite
Formula:
TlAs5S8
Some As may be replaced by Sb.
Colour:
Black
Lustre:
Dull
Hardness:
2
Specific Gravity:
4.5
Crystal System:
Monoclinic
Name:
In honor of Jan H. Bernard (1928-2018), Czech mineralogist, Associate professor of Geochemistry and Mineralogy at Charles University, Prague (1955-1967) and Central Geological Institute (Prague). He is the author or co-author of numerous publications including Mineralogy of Czechoslovakia (1969 & 1981), Minerals and their localities (2004).
Type Locality:
This page provides mineralogical data about Bernardite.
Classification of Bernardite
Approved
Approval Year:
1987
2/E.14-20
2.HD.50
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
D : With Tl
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
H : Sulfosalts of SnS archetype
D : With Tl
3.8.14.2
3 : SULFOSALTS
8 : 1 < ø < 2
3 : SULFOSALTS
8 : 1 < ø < 2
5.5.9
5 : Sulphosalts - Sulpharsenites and Sulphobismuthites (those containing Sn, Ge,or V are in Section 6)
5 : Sulpharsenites etc. of Tl
5 : Sulphosalts - Sulpharsenites and Sulphobismuthites (those containing Sn, Ge,or V are in Section 6)
5 : Sulpharsenites etc. of Tl
Physical Properties of Bernardite
Dull
Transparency:
Translucent
Colour:
Black
Streak:
Red
Hardness:
2 on Mohs scale
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
4.5 g/cm3 (Measured) 4.105 g/cm3 (Calculated)
Optical Data of Bernardite
Type:
Anisotropic
Reflectivity:
| 400nm | R1=29.6% | R2= 32.3% |
| 420nm | R1=28.9% | R2= 31.8% |
| 440nm | R1=28.1% | R2= 31.3% |
| 460nm | R1=27.4% | R2= 30.6% |
| 480nm | R1=26.8% | R2= 29.9% |
| 500nm | R1=26.0% | R2= 28.9% |
| 520nm | R1=25.4% | R2= 27.8% |
| 540nm | R1=25.0% | R2= 26.7% |
| 560nm | R1=24.5% | R2= 25.8% |
| 580nm | R1=24.0% | R2= 25.1% |
| 600nm | R1=23.6% | R2= 24.4% |
| 620nm | R1=23.3% | R2= 23.9% |
| 640nm | R1=23.1% | R2= 23.4% |
| 660nm | R1=22.9% | R2= 23.0% |
| 680nm | R1=22.8% | R2= 22.8% |
| 700nm | R1=22.8% | R2= 22.5% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 32.3%.
R1 shown in black, R2 shown in red
Chemical Properties of Bernardite
Formula:
TlAs5S8
Some As may be replaced by Sb.
Some As may be replaced by Sb.
Elements listed:
Crystallography of Bernardite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 15.647(4) Å, b = 8.038(3) Å, c = 10.750(3) Å
β = 91.27(3)°
β = 91.27(3)°
Ratio:
a:b:c = 1.947 : 1 : 1.337
Unit Cell V:
1,351.70 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Tabular crystals with prominent {100}, {012}, {210}, and {201}, {201}, {010}.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.46 Å | (65) |
| 4.28 Å | (74) |
| 3.72 Å | (55) |
| 3.68 Å | (63) |
| 3.07 Å | (65) |
| 3.06 Å | (100) |
| 2.68 Å | (59) |
Comments:
Calculated.
Geological Environment
Geological Setting:
Hydrothermal veins in Tl-As deposits
Type Occurrence of Bernardite
Synonyms of Bernardite
Other Language Names for Bernardite
Common Associates
| Edenharterite | PbTlAs3S6 |
| Erniggliite | Tl2SnAs2S6 |
| Hatchite | AgTlPbAs2S5 |
| Hutchinsonite | TlPbAs5S9 |
| Lorándite | TlAsS2 |
| Orpiment | As2S3 |
| Realgar | As4S4 |
| Stalderite | Tl(Cu,Ag)(Zn,Fe,Hg)2(As,Sb)2S6 |
| Wallisite | (Cu,Ag)TlPbAs2S5 |
Associated Minerals Based on Photo Data:
Related Minerals - Nickel-Strunz Grouping
| 2.HD.05 | Lorándite | TlAsS2 | Mon. 2/m : P21/b |
| 2.HD.05 | Weissbergite | TlSbS2 | Tric. 1 : P1 |
| 2.HD.15 | Christite | TlHgAsS3 | Mon. 2/m |
| 2.HD.20 | Jankovićite | Tl5Sb9(As,Sb)4S22 | Tric. 1 : P1 |
| 2.HD.25 | Rebulite | Tl5Sb5As8S22 | Mon. 2/m : P21/b |
| 2.HD.30 | Imhofite | Tl5.8As15.4S26 | Mon. 2/m |
| 2.HD.35 | Edenharterite | PbTlAs3S6 | Orth. |
| 2.HD.40 | Jentschite | TlPbAs2SbS6 | Mon. 2/m |
| 2.HD.45 | Hutchinsonite | TlPbAs5S9 | Orth. mmm (2/m 2/m 2/m) : Pbca |
| 2.HD.55 | Sicherite | TlAg2(As,Sb)3S6 | Orth. |
| 2.HD.60 | Gabrielite | Tl6Ag3Cu6(As,Sb)9S21 | Tric. 1 : P1 |
Related Minerals - Dana Grouping (8th Ed.)
| 3.8.14.1 | Parapierrotite | TlSb5S8 | Mon. m |
Related Minerals - Hey's Chemical Index of Minerals Grouping
| 5.5.1 | Lorándite | TlAsS2 | Mon. 2/m : P21/b |
| 5.5.2 | Ellisite | Tl3AsS3 | Trig. 3m : R3m |
| 5.5.3 | Imhofite | Tl5.8As15.4S26 | Mon. 2/m |
| 5.5.4 | Simonite | TlHgAs3S6 | Mon. 2/m |
| 5.5.6 | Christite | TlHgAsS3 | Mon. 2/m |
| 5.5.6 | Routhierite | Tl(Cu,Ag)(Hg,Zn)2(As,Sb)2S6 | Tet. 4 2m : I4 2m |
| 5.5.7 | Hutchinsonite | TlPbAs5S9 | Orth. mmm (2/m 2/m 2/m) : Pbca |
| 5.5.8 | Wallisite | (Cu,Ag)TlPbAs2S5 | Tric. |
| 5.5.10 | Vrbaite | Hg3Tl4As8Sb2S20 | Orth. mmm (2/m 2/m 2/m) : Cmca |
| 5.5.11 | Rebulite | Tl5Sb5As8S22 | Mon. 2/m : P21/b |
| 5.5.12 | Gillulyite | Tl2As7.5Sb0.3S13 | Mon. 2/m |
| 5.5.13 | Weissbergite | TlSbS2 | Tric. 1 : P1 |
| 5.5.14 | Rohaite | (Tl,Pb,K)2Cu8.7Sb2S4 | Orth. |
| 5.5.15 | Vaughanite | TlHgSb4S7 | Tric. |
| 5.5.16 | Chalcothallite | Tl2(Cu,Fe)6SbS4 | Tet. 4/mmm (4/m 2/m 2/m) : I4/mmm |
| 5.5.17 | Pierrotite | Tl2(Sb,As)10S16 | Orth. mm2 : Pna21 |
| 5.5.18 | Parapierrotite | TlSb5S8 | Mon. m |
| 5.5.19 | Criddleite | TlAg2Au3Sb10S10 | Mon. |
| 5.5.20 | Chabournéite | Tl4Pb2(Sb,As)20S34 | Tric. 1 : P1 |
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.
References for Bernardite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
American Mineralogist: 75: 1209.
Pašava, J., Pertlik, F., Stumpfl, E.F. and Zemann, J. (1989): Bernardite, a new thallium arsenic sulphosalt from Allchar, Macedonia, with a determination of the crystal structure. Mineralogical Magazine, 53, 531-538.
Internet Links for Bernardite
mindat.org URL:
https://www.mindat.org/min-636.html
Please feel free to link to this page.
Please feel free to link to this page.
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Localities for Bernardite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for further information on this occurrence.
? - Indicates mineral may be doubtful at this locality.
- Good crystals or important locality for species.
- World class for species or very significant.
(TL) - Type Locality for a valid mineral species.
(FRL) - First Recorded Locality for everything else (eg varieties).
All localities listed without proper references should be considered as questionable.
North Macedonia (TL) | |
| Pasava, J., Pertlik, F., Stumpfl, E. F., & Zemann, J. (1989). Bernardite, a new thallium arsenic sulphosalt from Allchar, Macedonia, with a determination of the crystal structure. Mineralogical Magazine, 53, 531-538. ; The Canadian Mineralogist Vol.32, pp. 649-665 (1994); Boevl, B., Bermanec, V., Serafimovski, T., Lepitkoval, S., & Mikulcic, S. (2001). Allchar Mineral Assemblage. Geologica Macedonica, Vol. 15-16, p. 1-23 (2001-2002) Suppl; Boev, I., Šorša, A., Tasev, G., Serafimovski, D., & Boev, B. (2017). Mineralogy and geochemistry of trace elements from Crven Dol–Alšar deposit (Republic of Macedonia). Geologica Macedonica, 31(1), 5-20. |
| Gunnar Färber specimens | |
Switzerland | |
| Graeser, S. & Edenharter, A. (1997): Jentschite (TlPbAs2SbS6) - a new sulfosalt mineral from Lengenbach, Binntal (Switzerland). Mineralogical Magazine 61, 131-137.; Graeser, St., Schwander, H., Wulf, R. & Edenharter, A. (1992): Erniggliite (Tl2SnAs2S6), a new mineral from Lengenbach, Binntal (Switzerland): description and crystal structure determination based on data from synchrotron radiation. Schweiz. Mineral. Petrogr. Mitt., 72, 293-305.; Graeser, S., Schwander, H., Wulf, R. (1995): Stalderite TlCu(Zn,Fe,Hg)2As2S6 - a new mineral related to routhierite: description and crystal structure determination. Schweizerische mineralogische und petrographische Mitteilungen 75, 337-345; Roth, P. (2016): Zwillinge seltener Lengenbach-Mineralien. Schweizer Strahler 50(2), 28-29 (in German and French). |
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Lengenbach Quarry, Fäld, Binn, Goms, Valais, Switzerland