Foshallasite
A discredited species name
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About Foshallasite
Formula:
Ca3[Si2O7] · 3H2O(?)
Originally described from Hackman Valley, Yukspor Mt., Khibiny Massif, Kola Peninsula, Murmanskaja Oblast', Northern Region, Russia.
Unique Identifiers
Mindat ID:
1586
Long-form identifier:
mindat:1:1:1586:4
IMA Classification of Foshallasite
Discredited
Classification of Foshallasite
9.HA.55
9 : SILICATES (Germanates)
H : Unclassified silicates
A : With Alkali and Alkali-earth Elements
9 : SILICATES (Germanates)
H : Unclassified silicates
A : With Alkali and Alkali-earth Elements
56.2.9.3
56 : SOROSILICATES Si2O7 Groups, With Additional O, OH, F and H2O
2 : Si2O7 Groups and O, OH, F, and H2O with cations in [4] and/or >[4] coordination
56 : SOROSILICATES Si2O7 Groups, With Additional O, OH, F and H2O
2 : Si2O7 Groups and O, OH, F, and H2O with cations in [4] and/or >[4] coordination
14.5.22
14 : Silicates not Containing Aluminum
5 : Silicates of Ca
14 : Silicates not Containing Aluminum
5 : Silicates of Ca
Optical Data of Foshallasite
Type:
Biaxial (-)
RI values:
nα = 1.535 nβ = 1.542 nγ = 1.549
2V:
Measured: 12° to 18°, Calculated: 88°
Max. Birefringence:
δ = 0.014
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:
None to Very Low
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 biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r > v weak
Chemistry of Foshallasite
Mindat Formula:
Ca3[Si2O7] · 3H2O(?)
Elements listed:
Common Impurities:
TR,Na
Synonyms of Foshallasite
Other Language Names for Foshallasite
German:Foshallasit
Spanish:Foshallasita
Related Minerals - Strunz-mindat Grouping
| 9.HA. | Shinichengite | Ca5[BSi2O7(OH)2]2 · 6H2O |
| 9.HA. | Kalyuzhnyite-(Ce) | NaKCaSrCeTi(Si8O21)OF(H2O)3 |
| 9.HA. | Moragite | Ca3TiSi2(Al2Si)O14 |
| 9.HA.05 | Ertixiite | Na2Si4O9 |
| 9.HA.10 | Kenyaite | Na2Si22O41(OH)8 · 6H2O |
| 9.HA.20 | Wawayandaite | Ca6Mn2BBe9Si6O23(OH,Cl)15 |
| 9.HA.25 | Magbasite | KBaFe3+Mg7Si8O22(OH)2F6 |
| 9.HA.35 | Demagistrisite | BaCa2Mn3+4(Si3O10)(Si2O7)(OH)4 · 3H2O |
| 9.HA.37 | Donwilhelmsite | CaAl4Si2O11 |
| 9.HA.40 | Kasatkinite | Ba2Ca8B5Si8O32(OH)3 · 6H2O |
| 9.HA.40 | 'Igumnovite' | Ca3Al2[SiO4]2[◻Cl4] |
| 9.HA.42 | Paqueite | Ca3TiSi2(Al,Ti,Si)3O14 |
| 9.HA.42 | Qeltite | Ca3TiSi2(Fe3+2Si)O14 |
| 9.HA.45 | Rippite | K2(Nb,Ti)2(Si4O12)O(O,F) |
| 9.HA.47 | Zagamiite | CaAl2Si3.5O11 |
| 9.HA.50 | Rudenkoite | Sr3(Al3.5Si3.5)O10(OH,O)8Cl2 · H2O |
| 9.HA.50 | 'α-Carnegieite' | NaAlSiO4 |
| 9.HA.52 | 'Atheriastite' | near Ca5MgFeAl6Si8O32 · 5H2O |
| 9.HA.57 | 'Bhreckite' | |
| 9.HA.60 | Nagelschmidtite | Ca7(SiO4)2(PO4)2 |
| 9.HA.65 | Caryochroite | [Na(Sr0.5Ca0.5)Mg]3[Fe3+8Mn(Fe2+0.5◻0.5)]10(Ti2Si12O37)(OH)14(H2O)3 |
| 9.HA.70 | Juanite | Ca10Mg4Al2Si11O39 · 4H2O or near |
| 9.HA.75 | Tacharanite | Ca12Al2Si18O33(OH)36 |
| 9.HA.80 | Oyelite | Ca10Si8B2O29 · 12.5H2O |
| 9.HA.85 | Denisovite | K14+x(Ca,Na,Mn,Fe)48[Si60O162]F16(Ox,OH4-x) · 2H2O |
| 9.HA.90 | Tiettaite | K4Na12Fe3+Si16O41(OH)4 · 2H2O |
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 Foshallasite
mindat.org URL:
https://www.mindat.org/min-1586.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Foshallasite
Localities for Foshallasite
Showing 1 localities.
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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 | |
| [World of Stones 95:5-6 |
Hackman Valley, Yukspor Mountain, Murmansk Oblast, Russia