Ezcurrite
A valid IMA mineral species - grandfathered
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About Ezcurrite
Formula:
Na4B10O17 · 7H2O
Colour:
Colorless
Lustre:
Vitreous, Silky
Hardness:
3 - 3½
Specific Gravity:
2.053
Crystal System:
Triclinic
Name:
For Juan Manuel de Ezcurra (1900-1970), manager of the Compañia Productora de Boratos SA and owner of the Tincalayu deposit, Argentina.
This page provides mineralogical data about Ezcurrite.
Unique Identifiers
Mindat ID:
1431
Long-form identifier:
mindat:1:1:1431:7
IMA Classification of Ezcurrite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Na2B5O7(OH)3·2H2O
First published:
1957
Classification of Ezcurrite
6.EB.10
6 : BORATES
E : Pentaborates
B : Ino-pentaborates
6 : BORATES
E : Pentaborates
B : Ino-pentaborates
26.5.5.1
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
5 : Pentaborates
26 : HYDRATED BORATES CONTAINING HYDROXYL OR HALOGEN
5 : Pentaborates
9.1.7
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 |
|---|---|---|
| Ezc | 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 Ezcurrite
Vitreous, Silky
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
3 - 3½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Excellent on {110}, good on {100}, fair {126}, poor on {110}{101}
Excellent on {110}, good on {100}, fair {126}, poor on {110}{101}
Density:
2.053 g/cm3 (Measured) 2.049 g/cm3 (Calculated)
Optical Data of Ezcurrite
Type:
Biaxial (-)
RI values:
nα = 1.468 nβ = 1.507 nγ = 1.529
2V:
Measured: 73° , Calculated: 72°
Max. Birefringence:
δ = 0.061
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 Ezcurrite
Mindat Formula:
Na4B10O17 · 7H2O
Element Weights:
Elements listed:
Crystallography of Ezcurrite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 8.598(2) Å, b = 9.570(2) Å, c = 6.576(2) Å
α = 102.75°, β = 107.5°, γ = 71.51°
α = 102.75°, β = 107.5°, γ = 71.51°
Ratio:
a:b:c = 0.898 : 1 : 0.687
Unit Cell V:
484.69 ų (Calculated from Unit Cell)
Z:
1
Morphology:
Bladed to fibrous prismatic crystals.
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) |
|---|---|---|---|---|---|---|---|
| 0000304 | Ezcurrite | Cannillo E, Dal Negro A, Ungaretti L (1973) The crystal structure of ezcurrite American Mineralogist 58 110-115 |  | 1973 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.936 Å | (100) |
| 3.074 Å | (38) |
| 4.494 Å | (29) |
| 3.135 Å | (19) |
| 2.780 Å | (19) |
| 2.039 Å | (10) |
| 3.302 Å | (8) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Ezcurrite
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 123927.
Geological Setting of Type Material:
Playa
Other Language Names for Ezcurrite
Common Associates
Associations Based on Photo Data:
| 2 photos of Ezcurrite associated with Tincalconite | Na2(B4O7) · 5H2O |
Related Minerals - Strunz-mindat Grouping
| 6.EB.05 | Larderellite | (NH4)B5O7(OH)2 · H2O |
| 6.EB.05 | Yarzhemskiite | K[B5O7(OH)2] · H2O |
| 6.EB.15 | Probertite | NaCa[B5O7(OH)4] · 3H2O |
| 6.EB.20 | Tertschite | Ca4B10O19 · 20H2O |
| 6.EB.25 | Priceite | Ca2B5O7(OH)5 · H2O |
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 Ezcurrite
mindat.org URL:
https://www.mindat.org/min-1431.html
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References for Ezcurrite
Reference List:
Muessig, Siegfried, Allen, R. D. (1957) Ezcurrite 2Na2O.5B2O3.7H2O), a new sodium borate from Argentina; occurrence, mineralogy, and associated minerals. Economic Geology, 52 (4) 426-437 doi:10.2113/gsecongeo.52.4.426
Muessig, Siegfried, Allen, R. D. (1957) Ezcurrite 2Na2O.5B2O3.7H2O), a new sodium borate from Argentina; occurrence, mineralogy, and associated minerals. Economic Geology, 52 (4) 426-437 doi:10.2113/gsecongeo.52.4.426
Hurlbut, C. S. Jr., Aristarain, L. F. (1967) Ezcurrite, 2Na2O·5B2O3·7H2O: A restudy. American Mineralogist, 52 (7-8) 1048-1059
Cannillo, Elio, Dal Negro, A., Ungaretti, Luciano (1973) The crystal structure of ezcurrite. American Mineralogist, 58 (1-2) 110-115
Frost, Ray L., López, Andrés, Theiss, Frederick L., Scholz, Ricardo, Belotti, Fernanda M. (2014) A vibrational spectroscopic study of the borate mineral ezcurrite Na4B10O17·7H2O – Implications for the molecular structure. Journal of Molecular Structure, 1070. 45-51 doi:10.1016/j.molstruc.2014.04.033
Localities for Ezcurrite
Showing 3 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 |
Mozambique | |
| Thomas et al. (2010) |
Serbia | |
| Putzolu et al. (2025) |
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Tincalayu Mine, Antofagasta de la Sierra Department, Catamarca Province, Argentina