Ameghinite Mineral Data

General Ameghinite Information

Chemical Formula:

NaB3O3(OH)4

Composition:

Molecular Weight = 171.45 gm

Sodium 13.41 % Na 18.08 % Na₂O

Boron 18.92 % B 60.91 % B₂O₃

Hydrogen 2.35 % H 21.02 % H₂O

Oxygen 65.32 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

NaB₃O₃(OH)₄

Environment:

Massive borax in a borate-rich playa.

IMA Status:

Approved IMA 1967

Locality:

Tincalayu borax deposit, Salar del Hombre Muerto, Salta Province, Argentina. Link to MinDat.org Location Data.

Name Origin:

Named for Carlos Ameghino (1865-1936) and Florentino Ameghino (1854-1911), both brothers and Argentine geologists.

Name Pronunciation:

Ameghinite + Pronunciation

Synonym:

ICSD 4219

PDF 20-1081

Ameghinite Image

Images:

Ameghinite

Comments: Aggregate of white, elongated crystals of ameghinite.
Location: Tincalayu Mine, Salta, Argentina. Scale: Specimen Size 1.5 x 1.5 x 1.5 cm.
© Tom Loomis / Dakota Matrix

Ameghinite Crystallography

Axial Ratios:

a:b:c =1.8648:1:0.6401

Cell Dimensions:

a = 18.428, b = 9.882, c = 6.326, Z = 8; beta = 104.387° V = 1,115.87 Den(Calc)= 2.04

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 3.065(1), 3.147(0.76), 2.548(0.29),

Physical Properties of Ameghinite

Cleavage:

{???} Distinct, {???} Imperfect

Color:

Colorless.

Density:

2.02 - 2.03, Average = 2.02

Diaphaneity:

Transparent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Hardness:

2-3 - Gypsum-Calcite

Luminescence:

Fluorescent and phosphorescent, Short UV=strong pale blue, Long UV=strong pale blue.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Ameghinite

Gladstone-Dale:

CI meas= -0.039 (Good) - where the CI = (1-KPDmeas/KC)
CI calc= -0.032 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2443,KPDmeas= 0.2461,KC= 0.2368
Ncalc = 1.48

Optical Data:

Biaxial (-), a=1.429, b=1.528, g=1.538, bire=0.1090

Pleochroism (x):

colorless.

Pleochroism (y):

colorless.

Calculated Properties of Ameghinite

Electron Density:

Bulk Density (Electron Density)=2.05 gm/cc
note: Specific Gravity of Ameghinite =2.04 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Ameghinite= 0.48 barns/electron
U=PE_Ameghinite x rElectron Density= 0.99 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Ameghinite is Not Radioactive

Ameghinite Classification

Dana Class:

25.03.01.01 (25)Anhydrous Borates Containing Hydroxyl or Halogen

(25.03)Dana Type

(25.03.01)Dana Group

25.03.01.01 Ameghinite NaB3O3(OH)4 C 2/c 2/m

Strunz Class:

06.CA.10 06 - BORATES

06.C - Triborates

06.CA -Neso-triborates

06.CA.10 Ameghinite NaB3O3(OH)4 C 2/c 2/m

Other Ameghinite Information

References:

NAME( AntBidBlaNic5) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Ameghinite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - GeoScienceWorld
6 - Google Images
7 - Google Scholar
8 - Handbook of Mineralogy (MinSocAm)
9 - Handbook of Mineralogy (UofA)
10 - MinDAT
11 - Mineralienatlas (Deutsch)
12 - Online Mineral Museum
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

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Print or Cut-and-Paste your Ameghinite Specimen Label here :

Ameghinite

NaB3O3(OH)4
Dana No: 25.03.01.01 Strunz No: 06.CA.10
Locality:

Notes:

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