Ameghinite
A valid IMA mineral species
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About Ameghinite
Carlos Ameghino
Formula:
Na(H4B3O7)
Colour:
Colourless
Lustre:
Vitreous
Hardness:
2 - 3
Specific Gravity:
2.030
Crystal System:
Monoclinic
Name:
Named in honour of the brothers Carlos Ameghino (16 June 1865 – 12 April 1936) and Florentino Ameghino (18 September 1854 – 6 August 1911) ( see https://www.mindat.org/photo-760469.html ), Argentine geologists.
This page provides mineralogical data about Ameghinite.
Unique Identifiers
Mindat ID:
195
Long-form identifier:
mindat:1:1:195:3
IMA Classification of Ameghinite
Approved
IMA Formula:
NaB3O3(OH)4
Approval year:
1966
Classification of Ameghinite
6.CA.10
6 : BORATES
C : Triborates
A : Neso-triborates
6 : BORATES
C : Triborates
A : Neso-triborates
25.3.1.1
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
3 : Triborates
25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
3 : Triborates
9.1.10
9 : Borates
1 : Borates of the alkalis and boric acid
9 : Borates
1 : Borates of the alkalis and boric acid
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 |
|---|---|---|
| Agh | 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 Ameghinite
Vitreous
Transparency:
Transparent
Colour:
Colourless
Hardness:
2 - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Very Good
{100}, very good; {001} and {010}, poor.
{100}, very good; {001} and {010}, poor.
Fracture:
Conchoidal
Density:
2.030(6) g/cm3 (Measured) 2.037 g/cm3 (Calculated)
Optical Data of Ameghinite
Type:
Biaxial (-)
RI values:
nα = 1.429 nβ = 1.528 nγ = 1.538
2V:
Measured: 33°
Max. Birefringence:
δ = 0.109
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
Chemistry of Ameghinite
Mindat Formula:
Na(H4B3O7)
Element Weights:
Elements listed:
Crystallography of Ameghinite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Setting:
C2/c
Cell Parameters:
a = 18.45 Å, b = 9.89 Å, c = 6.32 Å
β = 104.3°
β = 104.3°
Ratio:
a:b:c = 1.866 : 1 : 0.639
Unit Cell V:
1,117.48 ų (Calculated from Unit Cell)
Z:
8
Morphology:
Crystals are elongated along [010], may be bent or curved, showing {001}, {010}, {100}, {110}, {011}, {101}, {101}, {310}, to 5 mm; as cluster of crystals and nodular masses.
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) |
|---|---|---|---|---|---|---|---|
| 0000470 | Ameghinite | Dal Negro A, Pozas J M M, Ungaretti L (1975) The crystal structure of ameghinite American Mineralogist 60 879-883 |  | 1975 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.064 Å | (100) |
| 3.147 Å | (76) |
| 2.548 Å | (29) |
| 3.352 Å | (17) |
| 2.914 Å | (17) |
| 4.951 Å | (13) |
| 2.655 Å | (11) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Type Occurrence of Ameghinite
Place of Conservation of Type Material:
Natural History Museum, Paris, France; Harvard University, Cambridge, Massachusetts, 109054; National Museum of Natural History, Washington, D.C., USA, 137297.
Geological Setting of Type Material:
Formed in massive borax in a borate-rich playa.
Associated Minerals at Type Locality:
Synonyms of Ameghinite
Other Language Names for Ameghinite
Dutch:Ameghiniet
French:Ameghinite
German:Ameghinit
Norwegian:Ameghinit
Russian:Амегинит
Spanish:Ameghinita
Related Minerals - Strunz-mindat Grouping
| 6.CA.15 | Inderite | MgB3O3(OH)5 · 5H2O |
| 6.CA.20 | Kurnakovite | MgB3O3(OH)5 · 5H2O |
| 6.CA.25 | Inderborite | CaMg(H3B3O7)2 · 8H2O |
| 6.CA.30 | Meyerhofferite | CaB3O3(OH)5 · H2O |
| 6.CA.35 | Inyoite | Ca(H4B3O7)(OH) · 4H2O |
| 6.CA.40 | Solongoite | Ca2(H3B3O7)(OH)Cl |
| 6.CA.45 | Peprossiite-(Ce) | CeAl2(B3.67Si0.33)O10.67 |
| 6.CA.45 | Peprossiite-(Y) | YAl2(B3.67Si0.33)O10.67 |
| 6.CA.50 | Nifontovite | Ca3B6O6(OH)12(H2O)2 |
| 6.CA.55 | Olshanskyite | Ca2[B3O3(OH)6](OH) · 3H2O |
Fluorescence of Ameghinite
pale blue fluorescence and phosphorescence under SW and LW UV.
Other Information
Thermal Behaviour:
Tincalayu material [cm-1]: 3540sh, 3405, 3265s, 1530s, 1467, 1431, 1355, 1324s, 1264, 1210, 1178, 1139, 1061s, 1024s, 1004sh, 985sh, 875s, 855sh, 766s, 739, 721, 638s, 630w, 618, 531w, 523, 500, 477
Notes:
soluble in water
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 Ameghinite
mindat.org URL:
https://www.mindat.org/min-195.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Ameghinite
Reference List:
Aristarain, L. F., Hurlbut, C. S., Jr,, (1967) Ameghinite, Na2O·3B2O3·4H2O, a. new borate from Argentina. American Mineralogist, 52 (7-8) 935-945
Dal Negro, Alberto Alberto, Pozas, Jose M., Ungaretti, Luciano (1975) The crystal structure of ameghinite. American Mineralogist, 60 (9-10) 879-883
Localities for Ameghinite
Showing 1 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.
Argentina (TL) | |
| Aristarain et al. (1967) +4 other references |
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Tincalayu Mine, Antofagasta de la Sierra Department, Catamarca Province, Argentina