Sahamalite-(Ce)
A valid IMA mineral species - grandfathered
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About Sahamalite-(Ce)
Thure G. Sahama
Formula:
(Mg,Fe)(Ce,La,Nd)2(CO3)4
Colour:
Colourless
Lustre:
Vitreous
Specific Gravity:
4.30
Crystal System:
Monoclinic
Name:
Named in honor of Thure Georg Sahama (14 October 1910, Viipuri (Vyborg), Karelia, Finland - 8 March 1983), Professor of Geochemistry and Mineralogy, University of Helsinki, Finland, for his significant contributions to the understanding of the association and the abundance of the rare earths in eruptive rocks and in minerals. He helped describe nearly twenty new mineral species and was an honorary member of mineralogical societies from a number of countries. Originally named sahamalite, the suffix was added in 1987 to denote the dominant rare earth. It is pronounced sä'hä-mä-līt.
This page provides mineralogical data about Sahamalite-(Ce).
Unique Identifiers
Mindat ID:
3501
Long-form identifier:
mindat:1:1:3501:5
IMA Classification of Sahamalite-(Ce)
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ce2Mg(CO3)4
First published:
1953
Classification of Sahamalite-(Ce)
5.AD.05
5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
D : With rare-earth elements (REE)
5 : CARBONATES (NITRATES)
A : Carbonates without additional anions, without H2O
D : With rare-earth elements (REE)
14.4.2.1
14 : ANHYDROUS NORMAL CARBONATES
4 : Miscellaneous
14 : ANHYDROUS NORMAL CARBONATES
4 : Miscellaneous
11.8.21
11 : Carbonates
8 : Carbonates of the rare earths
11 : Carbonates
8 : Carbonates of the rare earths
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 |
|---|---|---|
| Shm-Ce | 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 Sahamalite-(Ce)
Vitreous
Transparency:
Transparent
Colour:
Colourless
Streak:
White
Cleavage:
Poor/Indistinct
{010} poor, {201} trace only.
{010} poor, {201} trace only.
Density:
4.30 g/cm3 (Measured) 4.30 g/cm3 (Calculated)
Optical Data of Sahamalite-(Ce)
Type:
Biaxial (-)
RI values:
nα = 1.679(2) nβ = 1.776(2) nγ = 1.807(2)
2V:
Measured: 57° , Calculated: 57°
Max. Birefringence:
δ = 0.128
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.
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.
Surface Relief:
Moderate
Dispersion:
r < v perceptible
Optical Extinction:
Y = b; Z ∧ c = 29°.
Pleochroism:
Non-pleochroic
Chemistry of Sahamalite-(Ce)
Mindat Formula:
(Mg,Fe)(Ce,La,Nd)2(CO3)4
Element Weights:
Crystallography of Sahamalite-(Ce)
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/a
Cell Parameters:
a = 5.894(1) Å, b = 16.116(3) Å, c = 4.612(1) Å
β = 106.54(1)°
β = 106.54(1)°
Ratio:
a:b:c = 0.366 : 1 : 0.286
Unit Cell V:
419.96 ų
Z:
2
Morphology:
Euhedral prisms flattened on {201}, complex morphology showing {010}, {011}, {111}, {131}, {120}, {021}, {142}, {211}, {110}, {201}, {323}, {251}, {230}, {112}, {343}; in subparallel-radiating aggregates.
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0015692 | Sahamalite-(Ce) | Pertlik F, Preisinger A (1983) Crystal structure of sahamalite (Mg,Fe)RE2(CO3)4 Tschermaks Mineralogische und Petrographische Mitteilungen 31 39-46 | 1983 | Mountain Pass mine, San Bernardino County, California | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.90 Å | (100) |
| 3.65 Å | (100) |
| 2.87 Å | (100) |
| 5.33 Å | (70) |
| 4.26 Å | (70) |
| 3.03 Å | (70) |
| 2.12 Å | (70b) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 36 : Carbonatites, kimberlites, and related igneous rocks |
Type Occurrence of Sahamalite-(Ce)
General Appearance of Type Material:
Tabular to prismatic crystals, to 0.2 mm, observed in thin section, intimately associated with parisite and bastnaesite.
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, number 106901.
Geological Setting of Type Material:
Accessory in baryte-dolomite-REE carbonatite.
Associated Minerals at Type Locality:
Other Language Names for Sahamalite-(Ce)
Related Minerals - Strunz-mindat Grouping
| 5.AD.15 | Rémondite-(La) | Na3(La,Ca,Na)3(CO3)5 |
| 5.AD.15 | Rémondite-(Ce) | Na3(Ce,Ca,Na)3(CO3)5 |
| 5.AD.15 | Petersenite-(Ce) | Na4(Ce,La,Nd)2(CO3)5 |
| 5.AD.20 | Paratooite-(La) | (La,Sr,Ca)4CuCa(Na,Ca)2(CO3)8 |
Other Information
Notes:
More resistant to acids than most normal carbonates.
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 Sahamalite-(Ce)
mindat.org URL:
https://www.mindat.org/min-3501.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Sahamalite-(Ce)
Reference List:
Jaffe, Howard W., Meyrowitz, Robert, Evans, and Howard T. (1953) Sahamalite, a new rare earth carbonate mineral. American Mineralogist, 38 (9-10) 741-754
Perlik, F., Preisinger, A. (1983) Crystal structure of sahamalite (Mg,Fe)RE2(CO3)4. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 31 (1). 39-46 doi:10.1007/bf01084760
Localities for Sahamalite-(Ce)
Showing 5 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 | |
| Ivashchenko et al. (2018, June) |
South Africa | |
| Ogungbuyi et al. (2022) |
USA (TL) | |
| Jaffe et al. (1953) +4 other references |
| Gammons et al. (2024) |
| Cosca et al. (1988) |
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Mountain Pass Mine, Mountain Pass, Mountain Pass District, Clark Mts, San Bernardino County, California, USA