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Olkhonskite
A valid IMA mineral species
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About Olkhonskite
Formula:
(Cr,V)2Ti3O9
Colour:
Black
Lustre:
Metallic
Hardness:
8
Specific Gravity:
4.48 (Calculated)
Crystal System:
Monoclinic
Name:
Named for the type locality, Olkhon Gate, Russia. Olkhon Gate is a narrow (1.5-2 km) in Lake Baikal between Olkhon Island and the western shore of Baikal.
Unique Identifiers
Mindat ID:
2985
Long-form identifier:
mindat:1:1:2985:4
IMA Classification of Olkhonskite
Approved
IMA Formula:
Cr3+2Ti4+3O9
Approval year:
1993
First published:
1994
Classification of Olkhonskite
4.CB.35
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
B : With medium-sized cations
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
B : With medium-sized cations
8.4.1.2
8 : MULTIPLE OXIDES CONTAINING NIOBIUM,TANTALUM OR TITANIUM
4 : A2B3O9
8 : MULTIPLE OXIDES CONTAINING NIOBIUM,TANTALUM OR TITANIUM
4 : A2B3O9
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 |
|---|---|---|
| Olk | 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 Olkhonskite
Metallic
Transparency:
Opaque
Colour:
Black
Streak:
Black
Hardness:
8 on Mohs scale
Hardness:
VHN65=1412 kg/mm2 - Vickers
Tenacity:
Brittle
Density:
4.48 g/cm3 (Calculated)
Optical Data of Olkhonskite
Anisotropism:
Weak
Bireflectance:
noted
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 440nm | 19.6% | 22.5% |
| 460nm | 18.2% | 21.1% |
| 470nm | 18.1% | 20.1% |
| 480nm | 18.2% | 20.1% |
| 500nm | 18.2% | 20.3% |
| 520nm | 18.4% | 20.1% |
| 540nm | 18.5% | 20.0% |
| 546nm | 18.5% | 19.9% |
| 560nm | 18.5% | 20.3% |
| 580nm | 18.4% | 20.2% |
| 589nm | 18.4% | 19.8% |
| 600nm | 18.4% | 20.1% |
| 620nm | 18.4% | 20.5% |
| 640nm | 18.5% | 21.0% |
| 650nm | 18.6% | 20.0% |
| 660nm | 19.5% | 21.3% |
| 680nm | 20.7% | 22.4% |
| 700nm | 20.8% | 22.6% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 22.6%.
R1 shown in black, R2 shown in red
Colour in reflected light:
Light gray
Pleochroism:
Weak
Comments:
in browns
Chemistry of Olkhonskite
Mindat Formula:
(Cr,V)2Ti3O9
Element Weights:
Elements listed:
Crystallography of Olkhonskite
Crystal System:
Monoclinic
Cell Parameters:
a = 7.03(1) Å, b = 5.02(1) Å, c = 18.83(1) Å
β = 119.60(5)°
β = 119.60(5)°
Ratio:
a:b:c = 1.4 : 1 : 3.751
Unit Cell V:
577.80 ų (Calculated from Unit Cell)
Z:
4
Comment:
Point Group: 2/m or m.; Space Group: C2/c, Cc, P21/c, P2/c, or P c. (by analogy to schreyerite)
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.75 Å | (100) |
| 1.386 Å | (100) |
| 2.88 Å | (70) |
| 2.43 Å | (70) |
| 1.426 Å | (70) |
| 2.14 Å | (50) |
| 1.660 Å | (50) |
Comments:
Ol'khonskiye Vorota Strait, Lake Baikal area, Russia. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 5: Initiation of plate tectonics | <3.5-2.5 |
| 40 : Regional metamorphism (greenschist, amphibolite, granulite facies) |
Type Occurrence of Olkhonskite
General Appearance of Type Material:
Platy crystals, to 150 µm, included in rutile.
Place of Conservation of Type Material:
A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, r1001.
Geological Setting of Type Material:
In quartzite schists.
Associated Minerals at Type Locality:
Synonyms of Olkhonskite
Other Language Names for Olkhonskite
Common Associates
Associations Based on Photo Data:
| 4 photos of Olkhonskite associated with Rutile | TiO2 |
| 1 photo of Olkhonskite associated with Karelianite | V3+2O3 |
| 1 photo of Olkhonskite associated with Quartz | SiO2 |
| 1 photo of Olkhonskite associated with Schreyerite | V3+2Ti4+3O9 |
Related Minerals - Strunz-mindat Grouping
| 4.CB. | Magnesiohögbomite-6N12S | Mg5Al11TiO23(OH) |
| 4.CB. | Kidodite | BaMg2Fe16O27 |
| 4.CB. | Ferrohögbomite-2N2S | [(Fe2+,Mg,Zn,Al)3(Al,Ti,Fe3+)8O15(OH)]2 |
| 4.CB. | Zhenruite | (MoO3)2 · H2O |
| 4.CB. | Fuyuanite | Mg7Nb6O18(OH)8 |
| 4.CB. | Virgilluethite | MoO3 · H2O |
| 4.CB. | Pengite | (Pb8Sb3+3)Σ11Sb5+9O35 |
| 4.CB.05 | Brizziite | NaSb5+O3 |
| 4.CB.05 | Tistarite | Ti3+2O3 |
| 4.CB.05 | Hematite | Fe2O3 |
| 4.CB.05 | Ecandrewsite | ZnTiO3 |
| 4.CB.05 | Melanostibite | Mn2+2Fe3+Sb5+O6 |
| 4.CB.05 | 'UM1998-11-O-AuHSb' | Au+2Sb3+O2(OH) |
| 4.CB.05 | Karelianite | V3+2O3 |
| 4.CB.05 | Corundum | Al2O3 |
| 4.CB.05 | Eskolaite | Cr2O3 |
| 4.CB.05 | Geikielite | MgTiO3 |
| 4.CB.05 | Akimotoite | MgSiO3 |
| 4.CB.05 | 'Unnamed (Fe-Cr Oxide)' | FeCrO3 |
| 4.CB.05 | 'Auroantimonate' | AuSbO3 |
| 4.CB.05 | Hemleyite | Fe2+SiO3 |
| 4.CB.05 | Ilmenite | Fe2+TiO3 |
| 4.CB.05 | Pyrophanite | Mn2+TiO3 |
| 4.CB.10 | Bixbyite-(Fe) | (Fe,Mn)2O3 |
| 4.CB.10 | Bixbyite-(Mn) | Mn3+2O3 |
| 4.CB.10 | Avicennite | Tl3+2O3 |
| 4.CB.15 | Armalcolite | MgTi4+2O5 |
| 4.CB.15 | Ferropseudobrookite | Fe2+Ti4+2O5 |
| 4.CB.15 | Griffinite | Al2Ti4+O5 |
| 4.CB.15 |
Ol'khonskiye Vorota Strait, Irkutsk Oblast, Russia