Rivadavite Mineral Data

General Rivadavite Information

Chemical Formula:

Na6MgB24O40•22(H2O)

Composition:

Molecular Weight = 1,458.00 gm

Sodium 9.46 % Na 12.75 % Na₂O

Magnesium 1.67 % Mg 2.76 % MgO

Boron 17.79 % B 57.30 % B₂O₃

Hydrogen 3.04 % H 27.18 % H₂O

Oxygen 68.04 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Na₆MgB₂₄O₄₀•22(H₂O)

Environment:

Sedimentary borate deposits; deposited from borate-rich hot springs.

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 Bernardino Rivadavia (1780-1845), first President of the Argentine Republic.

Name Pronunciation:

Rivadavite + Pronunciation

Synonym:

ICSD 31455

PDF 19-1211

Rivadavite Image

Images:

Rivadavite

Comments: Translucent white rivadavite nodule with some adhering earthy material.
Location: Tincalayu, Salta Province, Argentina. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Rivadavite Crystallography

Axial Ratios:

a:b:c =1.845:1:1.3892

Cell Dimensions:

a = 14.779, b = 8.01, c = 11.128, Z = 1; beta = 105.9° V = 1,266.93 Den(Calc)= 1.91

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 7.59(1), 14.2(1), 2.95(0.66),

Physical Properties of Rivadavite

Cleavage:

{100} Perfect, {101} Perfect, {010} Indistinct

Color:

Colorless, White.

Density:

1.905

Diaphaneity:

Transparent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Hardness:

3.5 - Copper Penny

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Rivadavite

Gladstone-Dale:

CI meas= -0.033 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.03 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2527,KPDmeas= 0.2534,KC= 0.2454
Ncalc = 1.47

Optical Data:

Biaxial (+), a=1.47, b=1.481, g=1.497, bire=0.0270, 2V(Calc)=82, 2V(Meas)=80.

Calculated Properties of Rivadavite

Electron Density:

Bulk Density (Electron Density)=1.93 gm/cc
note: Specific Gravity of Rivadavite =1.91 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Rivadavite= 0.47 barns/electron
U=PE_Rivadavite x rElectron Density= 0.91 barns/cc.

Radioactivity:

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

Rivadavite Classification

Dana Class:

26.06.01.01 (26)Hydrated Borates Containing Hydroxyl or Halogen

(26.06)Dana Type

(26.06.01)Dana Group

26.06.01.01 Rivadavite Na6MgB24O40•22(H2O) P 2₁/c 2/m

Strunz Class:

06.FA.20 06 - BORATES

06.F - Hexaborates

06.FA -Neso-hexaborates

06.FA.20 Rivadavite Na6MgB24O40•22(H2O) P 2₁/c 2/m

Other Rivadavite 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 Rivadavite :
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

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Ask about Rivadavite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
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Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Rivadavite

Na6MgB24O40•22(H2O)
Dana No: 26.06.01.01 Strunz No: 06.FA.20
Locality:

Notes: