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Sazhinite-(La)
A valid IMA mineral species
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About Sazhinite-(La)
Formula:
Na3La[Si6O15] · 2H2O
Colour:
Creamy white; colourless in plane-polarized light
Lustre:
Pearly
Hardness:
3
Specific Gravity:
2.64 (Calculated)
Crystal System:
Orthorhombic
Member of:
Name:
In allusion to its relationship to Sazhinite-(Ce), and its composition, with lanthanum being the dominant rare earth element cation.
Type Locality:
The La analogue of sazhinite-(Ce).
See also Unnamed (Sazhinite-related mineral I)and Unnamed (Sazhinite-related mineral II).
See also Unnamed (Sazhinite-related mineral I)and Unnamed (Sazhinite-related mineral II).
Unique Identifiers
Mindat ID:
27499
Long-form identifier:
mindat:1:1:27499:3
Similar Names
| Sazhinit | ||
| Sazhinita | ||
| Sazhinite | ||
| Sazhinite-(Ce) | A valid IMA mineral species | Na3CeSi6O15 · 2H2O |
IMA Classification of Sazhinite-(La)
Classification of Sazhinite-(La)
9.EA.30
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
9 : SILICATES (Germanates)
E : Phyllosilicates
A : Single nets of tetrahedra with 4-, 5-, (6-), and 8-membered rings
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 |
|---|---|---|
| Szi-La | 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 Sazhinite-(La)
Pearly
Transparency:
Transparent, Translucent
Colour:
Creamy white; colourless in plane-polarized light
Streak:
White
Hardness:
3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Parallel to {010} and {001}
Parallel to {010} and {001}
Density:
2.64 g/cm3 (Calculated)
Optical Data of Sazhinite-(La)
Type:
Biaxial (+)
RI values:
nα = 1.522 - 1.526 nβ = 1.526 - 1.53 nγ = 1.542 - 1.546
2V:
Measured: 46° , Calculated: 54°
Max. Birefringence:
δ = 0.020
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.
Optical Extinction:
X = c; Y = b; Z = a.
Chemistry of Sazhinite-(La)
Mindat Formula:
Na3La[Si6O15] · 2H2O
Element Weights:
Common Impurities:
Ca,K,REE
Crystallography of Sazhinite-(La)
Crystal System:
Orthorhombic
Class (H-M):
mm2 - Pyramidal
Space Group:
Pmm2
Cell Parameters:
a = 7.415 Å, b = 15.515 Å, c = 7.164 Å
Ratio:
a:b:c = 0.478 : 1 : 0.462
Unit Cell V:
824.2 ų
Morphology:
Crystals elongated along [001] and flattened on (010), exhibiting the forms {h0l}, {100} and {001}.
Twinning:
Not observed.
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) |
|---|---|---|---|---|---|---|---|
| 0014578 | Sazhinite-(La) | Camara F, Ottolini L, Devouard B, Garvie L A J, Hawthorne F C (2006) Sazhinite-(La), Na3LaSi6O15(H2O)2, a new mineral from the Aris phonolite, Nambia: description and crystal structure Mineralogical Magazine 70 405-418 | 2006 | Aris phonolite, Nambia | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.42 Å | (59) |
| 6.50 Å | (48) |
| 5.36 Å | (60) |
| 5.26 Å | (68) |
| 3.411 Å | (100) |
| 3.345 Å | (45) |
| 3.252 Å | (83) |
| 3.226 Å | (45) |
Comments:
From type description.
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 Sazhinite-(La)
General Appearance of Type Material:
Small elongate tabular crystals up to 1 mm long and 0.4 mm wide.
Place of Conservation of Type Material:
n.d.
Geological Setting of Type Material:
In vesicles within a phonolite, together with other species crystallized from late-stage hydrothermal fluids.
Associated Minerals at Type Locality:
Aris Quarries, Aris, Windhoek Rural, Khomas Region, Namibia