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Ashcroftine-(Ce)
Valid as an unnamed mineral
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Formula:
K5Na5(Ce,Ca)12Si28O70(OH)2(CO3)8 · 8H2O
Lustre:
Vitreous
Crystal System:
Tetragonal
Unique Identifiers
Mindat ID:
6809
Long-form identifier:
mindat:1:1:6809:9
Similar Names
| Ashcroftine-(Y) | A valid IMA mineral species - grandfathered | K5Na5(Y,Ca)12Si28O70(OH)2(CO3)8 · 8H2O |
IMA Classification of Ashcroftine-(Ce)
IMA status notes:
Unnamed (probably valid)
Approval history:
Unnamed, but probably valid.
Classification of Ashcroftine-(Ce)
9.DN.15
9 : SILICATES (Germanates)
D : Inosilicates
N : Inosilicates with 6-periodic double chains
9 : SILICATES (Germanates)
D : Inosilicates
N : Inosilicates with 6-periodic double chains
Physical Properties of Ashcroftine-(Ce)
Vitreous
Optical Data of Ashcroftine-(Ce)
Type:
Uniaxial (+)
RI values:
nω = 1.536 nε = 1.545
Max. Birefringence:
δ = 0.009
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 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.
Chemistry of Ashcroftine-(Ce)
Mindat Formula:
K5Na5(Ce,Ca)12Si28O70(OH)2(CO3)8 · 8H2O
Element Weights:
Crystallography of Ashcroftine-(Ce)
Crystal System:
Tetragonal
Related Minerals - Strunz-mindat Grouping
| 9.DN. | Letnikovite-(Ce) | (Na◻)Ca2Ce2[Si7O17(OH)]F4(H2O)4 |
| 9.DN.05 | Zektzerite | LiNaZrSi6O15 |
| 9.DN.05 | Emeleusite | Li2Na4Fe2Si12O30 |
| 9.DN.05 | Tuhualite | NaFe2+Fe3+Si6O15 |
| 9.DN.10 | Semenovite-(Ce) | Na8Ca2FeBe6Ce2Si14O40(OH)4F4 |
| 9.DN.15 | Ashcroftine-(Y) | K5Na5(Y,Ca)12Si28O70(OH)2(CO3)8 · 8H2O |
Radioactivity
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 Ashcroftine-(Ce)
mindat.org URL:
https://www.mindat.org/min-6809.html
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Please feel free to link to this page.
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References for Ashcroftine-(Ce)
Reference List:
