Grechishchevite
A valid IMA mineral species
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About Grechishchevite
Formula:
Hg2+3S2(Br,Cl,I)2
Colour:
Bright or dark orange, slowly darkening to brown-orange, then black.
Lustre:
Adamantine, Vitreous
Hardness:
2½
Specific Gravity:
7.23
Crystal System:
Tetragonal
Name:
Named by V.I. Vasil’ev, L.V. Usova, and N.A. Pal’chik in 1989 in honor of Oleg Konstantinovich Grechishchev (Олег Константинович Гречищев) (1936 – 2014), Institute of Geology, Novosibirsk, Russia, who did significant work on the Tuva mercury deposits.
This page provides mineralogical data about Grechishchevite.
Unique Identifiers
Mindat ID:
1744
Long-form identifier:
mindat:1:1:1744:8
IMA Classification of Grechishchevite
Approved
IMA Formula:
Hg2+3S2-2BrCl0.5I1-0.5
Approval year:
1988
First published:
1989
Classification of Grechishchevite
2.FC.15c
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
F : Sulfides of arsenic, alkalies; sulfides with halide, oxide, hydroxide, H2O
C : With Cl, Br, I (halide-sulfides)
2 : SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)
F : Sulfides of arsenic, alkalies; sulfides with halide, oxide, hydroxide, H2O
C : With Cl, Br, I (halide-sulfides)
10.3.5.1
10 : OXYHALIDES AND HYDROXYHALIDES
3 : A3(O,OH)2Xq
10 : OXYHALIDES AND HYDROXYHALIDES
3 : A3(O,OH)2Xq
6.5.4
6 : Sulphosalts - Sulphostannates, Sulphogermanates,Sulpharsenates, Sulphantimonates, Sulphovanadates and Sulphohalides
5 : Sulphohalides
6 : Sulphosalts - Sulphostannates, Sulphogermanates,Sulpharsenates, Sulphantimonates, Sulphovanadates and Sulphohalides
5 : Sulphohalides
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 |
|---|---|---|
| Gcv | 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 Grechishchevite
Adamantine, Vitreous
Transparency:
Transparent
Comment:
Luster vitreous to adamantine.
Colour:
Bright or dark orange, slowly darkening to brown-orange, then black.
Streak:
Deep yellow to yellow with a slight orange tint
Hardness:
2½ on Mohs scale
Hardness:
VHN25=88 - 116 kg/mm2 - Vickers
Tenacity:
Brittle
Cleavage:
Distinct/Good
Distinct cleavage parallel to prism elongation.
Distinct cleavage parallel to prism elongation.
Density:
7.23 g/cm3 (Measured) 7.16 g/cm3 (Calculated)
Comment:
Measured on synthetic material
Optical Data of Grechishchevite
Type:
Uniaxial (+)
RI values:
nω = 2 nε = 2
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.
Bireflectance:
Distinct, gray-white (R'e) to gray (R'o)
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 436nm | 19.2% | 22.8% |
| 460nm | 22.2% | 24.5% |
| 500nm | 18.9% | 21.4% |
| 546nm | 17.3% | 19.8% |
| 590nm | 16.5% | 18.8% |
| 620nm | 16.7% | 18.9% |
| 656nm | 15.9% | 18.1% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 24.5%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Gray-white
Internal Reflections:
Strong, light orange and orange
Pleochroism:
Visible
Comments:
Straw-yellow (E) to yellow (0).
Comments:
ω = > 2.0 ε = > 2.0
Chemistry of Grechishchevite
Mindat Formula:
Hg2+3S2(Br,Cl,I)2
Element Weights:
Crystallography of Grechishchevite
Crystal System:
Tetragonal
Cell Parameters:
a = 13.2 Å, c = 6.69 Å
Ratio:
a:c = 1 : 0.507
Unit Cell V:
1,165.67 ų (Calculated from Unit Cell)
Z:
8
Morphology:
prismatic crystals, granular, to 0.3 mm; in coatings and powdery masses
Comment:
Point Group: 4/m2/m2/m, 42m,or 4mm.; Space Group: [P4/mmm, P42m, or P4mm] (by analogy to synthetic material).
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
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
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) |
|---|---|---|---|---|---|---|---|
| 0005919 | Grechishchevite | Pervukhina N V, Vasil'ev V I, Borisov S V, Magarill S A, Naumov D Y (2003) The crystal structure of a polymorph of Hg3S2Br1Cl.5I.5 The Canadian Mineralogist 41 1445-1453 |  | 2003 | synthetic | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.95 Å | (60) |
| 3.02 Å | (60) |
| 2.65 Å | (100) |
| 2.60 Å | (40) |
| 2.341 Å | (40) |
| 2.180 Å | (30wide) |
| 1.873 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47g : [Halogen-bearing surface weathering minerals] |
Type Occurrence of Grechishchevite
Co-Type Localities:
General Appearance of Type Material:
Occurs on fracture walls as films consisting of minute prisms and groups of equant to slightly elongate grains to 0.2 mm (Arzak deposit); also as powdery masses and as concretions of short prismatic crystals to 0.3 mm (Kadyrel occurrence).
Place of Conservation of Type Material:
Central Siberian Geological Museum, Novosibirsk, Russia, number VI-31/1 (type).
Fersman Mineralogical Museum, Moscow, Russia, number 87988-90 (type).
Mining Museum, St. Petersburg, Russia, number 503/1, 503/2 (type).
Fersman Mineralogical Museum, Moscow, Russia, number 87988-90 (type).
Mining Museum, St. Petersburg, Russia, number 503/1, 503/2 (type).
Associated Minerals at Type Locality:
Synonyms of Grechishchevite
Other Language Names for Grechishchevite
Common Associates
Associations Based on Photo Data:
| 1 photo of Grechishchevite associated with Lavrentievite | Hg3S2Cl2 |
Related Minerals - Strunz-mindat Grouping
| 2.FC. | Demicheleite-(I) | BiSI |
| 2.FC.05 | Djerfisherite | K6(Fe,Cu,Ni)25S26Cl |
| 2.FC.05 | Owensite | (Ba,Pb)6(Cu,Fe,Ni)25S27 |
| 2.FC.05 | Thalfenisite | Tl6(Fe,Ni,Cu)25S26Cl |
| 2.FC.05 | Gmalimite | K6◻Fe2+24S27 |
| 2.FC.05 | 'Cu-djerfisherite' | K6(Cu,Fe)25S26Cl |
| 2.FC.05 | Zoharite | (Ba,K)6(Fe,Cu,Ni)25S27 |
| 2.FC.10 | Bartonite | K6Fe20S26S |
| 2.FC.10 | Chlorbartonite | K6Fe24S26(Cl,S) |
| 2.FC.15d | Radtkeite | Hg2+3S2ICl |
| 2.FC.15a | Lavrentievite | Hg3S2Cl2 |
| 2.FC.15a | Corderoite | Hg2+3S2Cl2 |
| 2.FC.15a | 'Arzakite' | Hg2+3S2(Br,Cl)2 |
| 2.FC.15b | Kenhsuite | Hg2+3S2Cl2 |
| 2.FC.20b | Iltisite | HgAgSCl |
| 2.FC.20c | Perroudite | Hg5Ag4S5(I,Br)2Cl2 |
| 2.FC.20a | Capgaronnite | AgHgClS |
| 2.FC.20d | Hanauerite | AgHgSI |
| 2.FC.25 | Demicheleite-(Cl) | BiSCl |
| 2.FC.25 | Demicheleite-(Br) | BiSBr |
Other Information
Notes:
Fragments blacken in 40% KOH; unaffected by HCl or HNO3.
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 Grechishchevite
mindat.org URL:
https://www.mindat.org/min-1744.html
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Please feel free to link to this page.
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References for Grechishchevite
Localities for Grechishchevite
Showing 2 localities.
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.
Russia (TL) | |
| Vasil’ev et al. (1989) +2 other references |
| Vasil’ev et al. (1989) +2 other references |
Quick NavTopAbout GrechishcheviteUnique IdentifiersIMA Classification Classification Mineral SymbolsPhysical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesCommon AssociatesStrunz-MindatOther InformationInternet Links References Localities Locality List
Kadyrel' Hg occurrence, Oorash-Khem River Valley, Uyuk Range, Pi-Khem District, Tuva, Russia