Rivadavite
A valid IMA mineral species
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About Rivadavite
Bernardino de la Trinidad Gónzalez Rivadavia y Rivadavia
Formula:
Na6Mg[B6O7(OH)6]4 · 10H2O
Colour:
Colourless, white
Lustre:
Vitreous, Silky
Hardness:
3½
Specific Gravity:
1.905
Crystal System:
Monoclinic
Name:
Named in honor of Bernardino Rivadavia (20 May 1780, Buenos Aires, Viceroyalty of the Río de la Plata – 2 September 1845, Cádiz, Spain), first president of the Argentine Republic. He was founder of the Museo de Historia Natural, today the Museo Argentino de Ciencias Naturales Bernardino Rivadavia. He also promoted research in mineralogy and mining in Argentina.
(Note that the name has nothing to do with the Rivadavia borate mine.)
(Note that the name has nothing to do with the Rivadavia borate mine.)
This page provides mineralogical data about Rivadavite.
Unique Identifiers
Mindat ID:
3426
Long-form identifier:
mindat:1:1:3426:1
IMA Classification of Rivadavite
Approved
IMA Formula:
Na6Mg[B6O7(OH)6]4·10H2O
Approval year:
1966
First published:
1967
Classification of Rivadavite
6.FA.20
6 : BORATES
F : Hexaborates
A : Neso-hexaborates
6 : BORATES
F : Hexaborates
A : Neso-hexaborates
26.6.1.1
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
6 : Hexaborates
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
6 : Hexaborates
9.2.15
9 : Borates
2 : Borates of Be and Mg
9 : Borates
2 : Borates of Be and Mg
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 |
|---|---|---|
| Riv | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Rivadavite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Rivadavite
Vitreous, Silky
Transparency:
Transparent
Comment:
Silky in aggregates
Colour:
Colourless, white
Streak:
White
Hardness:
3½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {100} {102}
poor on {010}
Perfect on {100} {102}
poor on {010}
Fracture:
Splintery
Density:
1.905(2) g/cm3 (Measured) 1.91 g/cm3 (Calculated)
Optical Data of Rivadavite
Type:
Biaxial (+)
RI values:
nα = 1.470(1) nβ = 1.481(1) nγ = 1.497(1)
2V:
Measured: 80° , Calculated: 82°
Max. Birefringence:
δ = 0.027
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
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. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Dispersion:
relatively weak r > v
Chemistry of Rivadavite
Mindat Formula:
Na6Mg[B6O7(OH)6]4 · 10H2O
Element Weights:
Crystallography of Rivadavite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Setting:
P21/m
Cell Parameters:
a = 15.870 Å, b = 8.010 Å, c = 22.256 Å
β = 116.40°
β = 116.40°
Ratio:
a:b:c = 1.981 : 1 : 2.779
Unit Cell V:
2,534.11 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Elongated crystals in subparallel massive aggregates
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 14.2 Å | (100) |
| 7.59 Å | (100) |
| 2.950 Å | (65) |
| 3.246 Å | (64) |
| 6.23 Å | (51) |
| 4.740 Å | (51) |
| 5.340 Å | (49) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Geological Setting:
Sedimentary borate deposits, hot springs
Type Occurrence of Rivadavite
General Appearance of Type Material:
Nearly spherical aggregates measuring from 1-9 cm in diameter.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, 109055.
National Museum of Natural History, Washington, D.C., USA, 137290, 137295.
National Museum of Natural History, Washington, D.C., USA, 137290, 137295.
Geological Setting of Type Material:
In a deposit of borax.
Associated Minerals at Type Locality:
Synonyms of Rivadavite
Other Language Names for Rivadavite
Related Minerals - Strunz-mindat Grouping
| 6.FA.05 | Aksaite | Mg[B6O7(OH)6] · 2H2O |
| 6.FA.10 | Mcallisterite | Mg2[B6O7(OH)6]2 · 9H2O |
| 6.FA.15 | Admontite | MgB6O10 · 7H2O |
| 6.FA.25 | Teruggite | Ca4Mg[AsO4]2[B6O7(OH)6]2 · 12H2O |
Other Information
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 Rivadavite
mindat.org URL:
https://www.mindat.org/min-3426.html
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Please feel free to link to this page.
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References for Rivadavite
Reference List:
Localities for Rivadavite
Showing 4 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) | |
| Helvaci +5 other references |
Turkey | |
| Helvaci +2 other references |
USA | |
| Crowley (1996) +1 other reference |
| Erd et al. (1970) +2 other references |
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Tincalayu Mine, Antofagasta de la Sierra Department, Catamarca Province, Argentina