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Ameghinite

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About AmeghiniteHide

Carlos Ameghino
Formula:
Na(H4B3O7)
Colour:
Colourless
Lustre:
Vitreous
Hardness:
2 - 3
Crystal System:
Monoclinic
Name:
Named in honor of the brothers Carlos Ameghino (16 June 1865 – 12 April 1936) and
Florentino Ameghino
(September 18, 1854 – August 6, 1911), Argentine geologists.
This page provides mineralogical data about Ameghinite.


Classification of AmeghiniteHide

Approved
Approval Year:
1966
6.CA.10

6 : BORATES
C : Triborates
A : Neso-triborates
25.3.1.1

25 : ANHYDROUS BORATES CONTAINING HYDROXYL OR HALOGEN
3 : Triborates
9.1.10

9 : Borates
1 : Borates of the alkalis and boric acid

Physical Properties of AmeghiniteHide

Vitreous
Transparency:
Transparent
Colour:
Colourless
Hardness:
2 - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Very Good
{100}, very good; {001} and {010}, poor.
Fracture:
Conchoidal

Optical Data of AmeghiniteHide

Type:
Biaxial (-)
RI values:
nα = 1.429 nβ = 1.528 nγ = 1.538
Max Birefringence:
δ = 0.109
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
none

Chemical Properties of AmeghiniteHide

Formula:
Na(H4B3O7)
IMA Formula:
NaB3O3(OH)4

Crystallography of AmeghiniteHide

Crystal System:
Monoclinic
Cell Parameters:
a = 18.45 Å, b = 9.89 Å, c = 6.32 Å
β = 104.3°
Ratio:
a:b:c = 1.866 : 1 : 0.639
Unit Cell V:
1,117.48 ų (Calculated from Unit Cell)
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.

Type Occurrence of AmeghiniteHide

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 AmeghiniteHide

Other Language Names for AmeghiniteHide

Related Minerals - Nickel-Strunz GroupingHide

6.CA.15InderiteMgB3O3(OH)5 · 5H2OMon. 2/m : P21/b
6.CA.20KurnakoviteMgB3O3(OH)5 · 5H2OTric. 1 : P1
6.CA.25InderboriteCaMg(H3B3O7)2 · 8H2OMon. 2/m
6.CA.30MeyerhofferiteCa2(H3B3O7)2 · 4H2OTric. 1 : P1
6.CA.35InyoiteCa(H4B3O7)(OH) · 4H2OMon. 2/m
6.CA.40SolongoiteCa2(H3B3O7)(OH)ClMon.
6.CA.45Peprossiite-(Ce)(Ce,La)(Al3O)2/3B4O10Hex. 6 m2 : P62m
6.CA.50NifontoviteCa3B6O6(OH)12(H2O)2Mon.
6.CA.55OlshanskyiteCa2[B3O3(OH)6](OH) · 3H2O

Related Minerals - Hey's Chemical Index of Minerals GroupingHide

9.1.1SassoliteH3BO3Tric. 1 : P1
9.1.2MetaboriteHBO2Iso.
9.1.3DiomigniteLi2[B4O7]Tet.
9.1.4BiringucciteNa2B5O8(OH) · H2OMon.
9.1.5NasiniteNa2[B5O8(OH)] · 2H2OOrth.
9.1.6KerniteNa2[B4O6(OH)2] · 3H2OMon. 2/m : P2/b
9.1.7EzcurriteNa4B10O17 · 7H2OTric. 1 : P1
9.1.8TincalconiteNa2(B4O7) · 5H2OTrig. 3 2 : R3 2
9.1.9BoraxNa2(B4O5)(OH)4 · 8H2OMon. 2/m : B2/b
9.1.11SborgiteNa[B5O6(OH)4] · 3H2OMon.
9.1.12AristarainiteNa2MgB12O20 · 8H2OMon. 2/m : P21/b
9.1.13SantiteK[B5O6(OH)4] · 2H2OOrth.
9.1.14Larderellite(NH4)B5O7(OH)2 · H2OMon.
9.1.15Ammonioborite(NH4)2[B5O6(OH)4]2 · H2OMon. 2/m : B2/b
9.1.16Rhodizite(K,Cs)Al4Be4(B,Be)12O28Iso. 4 3m : P4 3m

Fluorescence of AmeghiniteHide

pale blue fluorescence and phosphorescence under SW and LW UV.

Other InformationHide

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.

References for AmeghiniteHide

Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Aristarain, L.F., Hurlbut, C.S. (1967) Ameghinite, Na2O·3B2O3·4H2O, a new borate from Argentina. American Mineralogist: 52: 935-946.
Dal Negro, A., Martin Pozas, J.M., Ungaretti, L. (1975) The crystal structure of ameghinite. American Mineralogist: 60: 879-883.
Chukanov, N.V. (2014): Infrared spectra of mineral species: Extended library. Springer (Springer Geochemistry/Mineralogy), vol. 1, Dordrecht, 1726 pp.

Internet Links for AmeghiniteHide

Localities for AmeghiniteHide

ⓘ - Click for 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). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (eg from pseudomorphs.)

All localities listed without proper references should be considered as questionable.
Argentina (TL)
 
  • Salta
    • Los Andes department
      • Salar del Hombre Muerto
Amer.Min.(1967) 52, 935-945; Am Min 58:308-313; Alonso, R. N. (1999). On the origin of La Puna borates. Acta geológica hispánica, 34(2), 141-166.; CAHIT HELVACI & RICARDO N. ALONSO (2000) Borate Deposits of Turkey and Argentina; A Summary and Geological Comparison. Turkish Journal of Earth Sciences, 9:1-27.
Mineral and/or Locality  
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