Rohaite
A valid IMA mineral species
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Formula:
(Tl,Pb,K)2Cu8.7Sb2S4
Colour:
Black
Lustre:
Metallic
Hardness:
3 - 3½
Crystal System:
Orthorhombic
Name:
Named after John Rose-Hansen (2 May 1937, Copenhagen, Denmark - 18 September 2015), professor of mineralogy, University of Copenhagen, Denmark.
This page provides mineralogical data about Rohaite.
Unique Identifiers
Mindat ID:
3439
Long-form identifier:
mindat:1:1:3439:1
GUID
(UUID V4):
(UUID V4):
f0d70c65-74d7-40dc-9390-a331f843ad89
IMA Classification of Rohaite
Approved
IMA Formula:
(Tl,Pb,K)2Cu8.7Sb2S4
First published:
1978
Classification of Rohaite
2.BD.35
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
B : Metal Sulfides, M: S > 1: 1 (mainly 2: 1)
D : With Hg, Tl
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
B : Metal Sulfides, M: S > 1: 1 (mainly 2: 1)
D : With Hg, Tl
3.7.16.1
3 : SULFOSALTS
7 : ø = 2
3 : SULFOSALTS
7 : ø = 2
5.5.14
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
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 |
|---|---|---|
| Roh | 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 Rohaite
Metallic
Transparency:
Opaque
Colour:
Black
Comment:
In reflected light, yellowish cream to dull bluish gray.
Hardness:
3 - 3½ on Mohs scale
Hardness Data:
Could not be measured
Tenacity:
Malleable
Optical Data of Rohaite
Anisotropism:
Strong, yellowish-cream to black
Reflectivity:
| Wavelength | R1 | R2 |
|---|---|---|
| 481nm | 24.5% | 32.0% |
| 546nm | 22.3% | 32.4% |
| 590nm | 21.8% | 32.0% |
| 650nm | 20.8% | 31.8% |
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 32.4%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Yellowish-cream to dull bluish-gray
Pleochroism:
Strong
Comments:
Strong in air and oil
Comments:
Optically positive
Chemistry of Rohaite
Mindat Formula:
(Tl,Pb,K)2Cu8.7Sb2S4
Common Impurities:
Pb,Fe
Crystallography of Rohaite
Crystal System:
Orthorhombic
Cell Parameters:
a = 7.602(2) Å, b = 3.801(2) Å, c = 20.986(8) Å
Ratio:
a:b:c = 2 : 1 : 5.521
Unit Cell V:
606.39 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Rarely as euhedral and subhedral crystals (to 0.5 mm); in patchy aggregates.
Comment:
Space group P222, Pmm2, or Pmmm.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.800 Å | (90) |
| 3.078 Å | (100) |
| 2.393 Å | (100) |
| 1.902 Å | (90) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| High-𝑇 alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Rohaite
General Appearance of Type Material:
Grains from 0.05-0.5 mm.
Place of Conservation of Type Material:
University of Copenhagen, Geological Museum, Copenhagen, Denmark, 1979.1212 (cotype).
Geological Setting of Type Material:
In a vein rich in analcime and sodalite in an alkalic intrusive.
Associated Minerals at Type Locality:
Reference:
Karup-Møller, S. (1978) Primary and secondary ore minerals associated with cuprostibite. Bulletin Grønlands Geologiske Undersøgelse, 126, 23-47.
Synonyms of Rohaite
Other Language Names for Rohaite
Related Minerals - Strunz-mindat Grouping
| 2.BD. | UM2004-33-S:AgCuHgSe | (Ag,Cu)8Hg3(S,Se)7 |
| 2.BD. | Vrančiceite | Cu10Hg3S8 |
| 2.BD.05 | Imiterite | Ag2HgS2 |
| 2.BD.10 | Gortdrumite | Cu24Fe2Hg9S23 |
| 2.BD.15 | Balkanite | Cu9Ag5HgS8 |
| 2.BD.15 | Danielsite | (Cu,Ag)14HgS8 |
| 2.BD.20 | Donharrisite | Ni3HgS3 |
| 2.BD.25 | Carlinite | Tl2S |
| 2.BD.30 | Bukovite | (Cu3Fe)Σ4Tl2Se4 |
| 2.BD.30 | Murunskite | K2(Cu,Fe)4S4 |
| 2.BD.30 | Thalcusite | Tl2Cu3FeS4 |
| 2.BD.40 | Chalcothallite | Tl2(Cu,Fe)6SbS4 |
| 2.BD.45 | Sabatierite | TlCu6Se4 |
| 2.BD.50 | Crookesite | Cu7(Tl, Ag)Se4 |
| 2.BD.55 | Brodtkorbite | Cu2HgSe2 |
Other Information
Notes:
Alters readily to a mixture of digenite and senarmontite.
Etch tests with HgCl2, KOH, KCN, and FeCl3 were negative. With HCl (1:1) the mineral turned slightly steel-bluish gray, with HNO3 (1:1) the polished surface is destroyed and the mineral turns black.
Etch tests with HgCl2, KOH, KCN, and FeCl3 were negative. With HCl (1:1) the mineral turned slightly steel-bluish gray, with HNO3 (1:1) the polished surface is destroyed and the mineral turns black.
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 Rohaite
mindat.org URL:
https://www.mindat.org/min-3439.html
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References for Rohaite
Reference List:
Localities for Rohaite
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for references and 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.
Greenland | |
| American Mineralogist (1980) +1 other reference |
| Petersen et al. (2005) |
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