Koashvite
A valid IMA mineral species
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About Koashvite
Formula:
Na6(Ca,Mn)(Ti,Fe)Si6O18 · H2O
Colour:
Pale yellow
Lustre:
Vitreous
Hardness:
6
Specific Gravity:
2.98 - 3.02
Crystal System:
Orthorhombic
Member of:
Name:
Named by Y.L. Kapustin, Z.V. Pudovkina, A.V. Bykova, and G.V. Lyubomilova in 1974 for the type locality of Koashva Open Pit, Russia, an important locality that is the type locality for many minerals.
Type Locality:
Unique Identifiers
Mindat ID:
2230
Long-form identifier:
mindat:1:1:2230:5
IMA Classification of Koashvite
Approved
IMA Formula:
Na6CaTi4+Si6O18
Approval year:
1973
First published:
1974
Classification of Koashvite
9.CJ.15c
9 : SILICATES (Germanates)
C : Cyclosilicates
J : [Si6O18]12- 6-membered single rings (sechser-Einfachringe), without insular complex anions
9 : SILICATES (Germanates)
C : Cyclosilicates
J : [Si6O18]12- 6-membered single rings (sechser-Einfachringe), without insular complex anions
61.1.2b.2
61 : CYCLOSILICATES Six-Membered Rings
1 : Six-Membered Rings with [Si6O18] rings; possible (OH) and Al substitution
61 : CYCLOSILICATES Six-Membered Rings
1 : Six-Membered Rings with [Si6O18] rings; possible (OH) and Al substitution
14.9.38
14 : Silicates not Containing Aluminum
9 : Silicates of Ti
14 : Silicates not Containing Aluminum
9 : Silicates of Ti
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 |
|---|---|---|
| Koa | 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 Koashvite
Vitreous
Transparency:
Transparent
Colour:
Pale yellow
Hardness:
6 on Mohs scale
Hardness:
VHN20=680 - 740 kg/mm2 - Vickers
Fracture:
Conchoidal
Density:
2.98 - 3.02 g/cm3 (Measured) 3.069 g/cm3 (Calculated)
Optical Data of Koashvite
Type:
Biaxial (-)
RI values:
nα = 1.637 nβ = 1.643 nγ = 1.648
2V:
Measured: 82° to 84°, Calculated: 84°
Max. Birefringence:
δ = 0.011
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:
Moderate
Dispersion:
weak
Chemistry of Koashvite
Mindat Formula:
Na6(Ca,Mn)(Ti,Fe)Si6O18 · H2O
Element Weights:
Common Impurities:
Mg,K
Crystallography of Koashvite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 10.179(1) Å, b = 20.899(2) Å, c = 7.335(1) Å
Ratio:
a:b:c = 0.487 : 1 : 0.351
Unit Cell V:
1,560.38 ų (Calculated from Unit Cell)
Z:
4
Comment:
Space Group: Pmnb
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.581 Å | (100) |
| 1.820 Å | (70) |
| 3.66 Å | (50) |
| 3.28 Å | (50) |
| 1.504 Å | (50) |
| 2.620 Å | (40) |
| 1.476 Å | (40) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 35 : Ultra-alkali and agpaitic igneous rocks |
Type Occurrence of Koashvite
Place of Conservation of Type Material:
A.E. Fersman Mineralogical Museum, Academy of Sciences, Moscow, Russia, 75148; National School of Mines, Paris, France.
Geological Setting of Type Material:
veinlets replacing lomonosovite
Associated Minerals at Type Locality:
Synonyms of Koashvite
Other Language Names for Koashvite
Relationship of Koashvite to other Species
Member of:
Related Minerals - Strunz-mindat Grouping
| 9.CJ. | Zolotarevite | Na5Zr[Si6O15(OH)3] · 3H2O |
| 9.CJ. | 'Avdeevite' | NaAl4(Be5Li)(Si6O18)2(H2O)1-2 |
| 9.CJ. | 'Beryllocordierite-Na' | NaMg4(Al5Be)(AlSi5O18)2 · 2H2O |
| 9.CJ. | Sachanbińskiite | NaMn4(Al5Be)(AlSi5O18)2 · 2H2O |
| 9.CJ. | Nakkaalaaqite | K2[Na3Ca]LiCa2Ti2Be4Si12O38 |
| 9.CJ.05 | Johnkoivulaite-(Cs) | Cs[Be2B]Mg2Si6O18 |
| 9.CJ.05 | Beryl | Be3Al2(Si6O18) |
| 9.CJ.05 | Bazzite | Be3Sc2(Si6O18) |
| 9.CJ.05 | Ferroindialite | (Fe2+,Mg)2Al4Si5O18 |
| 9.CJ.05 va | 'Vorobyevite' | Be3Al2(Si6O18) |
| 9.CJ.05 | Stoppaniite | Be3Fe3+2(Si6O18) · H2O |
| 9.CJ.05 | Indialite | Mg2Al3(AlSi5O18) |
| 9.CJ.10 | Sekaninaite | Fe2+2Al4Si5O18 |
| 9.CJ.10 | Cordierite | Mg2Al4Si5O18 |
| 9.CJ.15a | Zirsinalite | Na6(Ca,Mn2+,Fe2+)Zr(Si6O18) |
| 9.CJ.15a | Kapustinite | Na6ZrSi6O16(OH)2 |
| 9.CJ.15a | Townendite | Na8ZrSi6O18 |
| 9.CJ.15a | Combeite | Na4.5Ca3.5Si6O17.5(OH)0.5 |
| 9.CJ.15a | Kazakovite | Na6Mn2+Ti(Si6O18) |
| 9.CJ.15a | Tisinalite | Na3H3(Mn,Ca,Fe)TiSi6(O,OH)18 · 2H2O |
| 9.CJ.15a | Lovozerite | Na2Ca(Zr,Ti)(Si6O12)[(OH)4O2] · H2O |
| 9.CJ.15a | Litvinskite | Na2(◻,Na,Mn)ZrSi6O12(OH,O)6 |
| 9.CJ.15b | Imandrite | Na12Ca3Fe3+2(Si6O18)2 |
| 9.CJ.25 | Baratovite | KCa7(Ti,Zr)2Li3Si12O36F2 |
| 9.CJ.25 | Aleksandrovite | KCa7Sn2Li3Si12O36F2 |
| 9.CJ.25 | Katayamalite | KLi3Ca7Ti2(SiO3)12(OH)2 |
| 9.CJ.30 | Dioptase | CuSiO3 · H2O |
| 9.CJ.35 | Kostylevite | K2Zr(Si3O9) · H2O |
| 9.CJ.40 | Petarasite | Na5Zr2(Si6O18)(Cl,OH) · 2H2O |
| 9.CJ.45 | Gerenite-(Y) | (Ca,Na)2(Y,REE)3Si6O18 · 2H2O |
| 9.CJ.50 | Odintsovite | K2Na4Ca3Ti2Be4Si12O38 |
| 9.CJ.55 | Mathewrogersite | Pb7FeAl3GeSi12O36(OH,H2O)6 |
| 9.CJ.60 | Pezzottaite-(Cs) | Cs(Be2Li)Al2(Si6O18) |
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 Koashvite
mindat.org URL:
https://www.mindat.org/min-2230.html
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References for Koashvite
Reference List:
Localities for Koashvite
Showing 3 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) | |
| [World of Stones 95:5-6 +2 other references |
| Pekov (1998) | |
| Khomyakov et al. (1983) |
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Koashva Open Pit, Koashva Mt, Murmansk Oblast, Russia