Esperanzaite
A valid IMA mineral species
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About Esperanzaite
Formula:
NaCa2Al2(AsO4)2(OH)F4 · 2H2O
Colour:
Pale blue-green
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
3.24
Crystal System:
Monoclinic
Name:
Named after the discovery locality, the La Esperanza Mine, Durango, Mexico.
This page provides mineralogical data about Esperanzaite.
Unique Identifiers
Mindat ID:
6919
Long-form identifier:
mindat:1:1:6919:5
IMA Classification of Esperanzaite
Approved
IMA Formula:
NaCa2Al2(As5+O4)2F4(OH)·2H2O
Approval year:
1998
First published:
1999
Classification of Esperanzaite
8.DM.05
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
M : With large and medium-sized cations, (OH, etc.):RO4 > 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
M : With large and medium-sized cations, (OH, etc.):RO4 > 2:1
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 |
|---|---|---|
| Epz | 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 Esperanzaite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Esperanzaite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Pale blue-green
Streak:
White
Hardness:
4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Parallel to c.
Parallel to c.
Fracture:
None observed
Density:
3.24 g/cm3 (Measured) 3.36 g/cm3 (Calculated)
Optical Data of Esperanzaite
Type:
Biaxial (-)
RI values:
nα = 1.580(1) nβ = 1.588(1) nγ = 1.593(1)
2V:
Measured: 74° , Calculated: 76°
Max. Birefringence:
δ = 0.013
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:
r < v moderate
Optical Extinction:
Y = b; X ∧ c = 35°; Z ∧ a = 50.5°.
Pleochroism:
Non-pleochroic
Chemistry of Esperanzaite
Mindat Formula:
NaCa2Al2(AsO4)2(OH)F4 · 2H2O
Element Weights:
Crystallography of Esperanzaite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/m
Setting:
P21/m
Cell Parameters:
a = 9.687(5) Å, b = 10.7379(6) Å, c = 5.5523(7) Å
β = 105.32°
β = 105.32°
Ratio:
a:b:c = 0.902 : 1 : 0.517
Unit Cell V:
557.02 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Botryoidal patches and radiating crystals in spheres.
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) |
|---|---|---|---|---|---|---|---|
| 0005592 | Esperanzaite | Foord E E, Hughes J M, Cureton F E, Maxwell C H, Falster A U, Sommer A J, Hlava P F (1999) Esperanzaite, NaCa2Al2(AsO4)2F4(OH).2H2O, a new mineral species from the La Esperanza mine, Mexico: Descriptive mineralogy and atomic arrangement The Canadian Mineralogist 37 67-72 |  | 1999 | La Esperanza mine, Mexico | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.364 Å | (80) |
| 4.796 Å | (80) |
| 3.801 Å | (80) |
| 3.527 Å | (90) |
| 2.966 Å | (100) |
| 2.700 Å | (90) |
Comments:
La Esperanza mine, Durango, Mexico. The data are from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| 47g : [Halogen-bearing surface weathering minerals] |
Type Occurrence of Esperanzaite
General Appearance of Type Material:
Botryoidal pale blue-green (seafoam green) patches up to 8 mm across and separated spheres up to 1.5 mm in diameter of radiating crystals.
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 171530.
Geological Setting of Type Material:
Found on an altered rhyolite.
Associated Minerals at Type Locality:
Synonyms of Esperanzaite
Other Language Names for Esperanzaite
Related Minerals - Strunz-mindat Grouping
| 8.DM. | Tomsquarryite | NaMgAl3(PO4)2(OH)6 · 8H2O |
| 8.DM. | Elliottite | NaMgAl3(PO4)2F6 · 9H2O |
| 8.DM. | Betpakdalite-FeFe | [Fe3+2 (H2O)15(OH)2Fe3+(H2O)6][Mo8As2Fe3+3O37] |
| 8.DM. | Penriceite | [Mg(H2O)6][Na(H2O)2Al3(PO4)2F6] · H2O |
| 8.DM. | Betpakdalite-CaMg | [Ca2(H2O)17Mg(H2O)6][Mo8As2Fe3+3O36(OH)] |
| 8.DM. | Chinnerite | [Mg(H2O)6]Na(H2O)2Al3(PO4)2F6 |
| 8.DM. | Sarrochite | [Ca4(H2O)38][Mo8P2Fe3+3O37(OH)] |
| 8.DM.05 | Morinite | NaCa2Al2(PO4)2(OH)F4 · 2H2O |
| 8.DM.10 | Alexshubnikovite | Ca2Cu9(AsO4)4(OH)9Cl(H2O)8 · 2H2O |
| 8.DM.10 | Tangdanite | Ca2Cu9(AsO4)4(SO4)0.5(OH)9 · 9H2O |
| 8.DM.10 | Tyrolite | Ca2Cu9(AsO4)4(CO3)(OH)8 · 11H2O |
| 8.DM.15 | Melkovite | [Ca2(H2O)15Ca(H2O)6][Mo8P2Fe3+3O36(OH)] |
| 8.DM.15 | Betpakdalite-NaCa | [Na2(H2O)17Ca(H2O)6][Mo6+8As5+2Fe3+3O34(OH)3] |
| 8.DM.15 | Betpakdalite-CaCa | [Ca2(H2O)17Ca(H2O)6][Mo6+8As5+2Fe3+3O36(OH)] |
| 8.DM.20 | Phosphovanadylite-Ba | Ba[V4+4P2O8(OH)8] · 12H2O |
| 8.DM.20 | Phosphovanadylite-Ca | Ca[V4+4P2O12(OH)4] · 12H2O |
| 8.DM.25 | Yukonite | Ca3Fe3+(AsO4)2(OH)3 · 5H2O |
| 8.DM.30 | Uduminelite | Ca3Al8(PO4)2O12 · 2H2O |
| 8.DM.35 | Aldermanite | [Mg(H2O)6][Na(H2O)2Al3(PO4)2(OH,F)6] · H2O |
| 8.DM.35 | 'Azovskite' | Fe3+3(PO4)(OH)6 or near |
| 8.DM.35 | Delvauxite | CaFe4(PO4,SO4)2(OH)8 · 4-6H2O not confirmed |
| 8.DM.40 | Santafeite | (Na,Ca,Sr)12(Mn2+,Fe3+,Al,Mg)8Mn4+8(VO4)16(OH,O)20 · 8H2O |
| 8.DM.55 | Tapiaite | Ca5Al2(AsO4)4(OH)4 · 12H2O |
| 8.DM.60 | Alcantarillaite | [Fe3+0.5(H2O)4][CaAs3+2(Fe3+2.5W6+0.5)(AsO4)2O7] |
Fluorescence of Esperanzaite
Not fluorescent.
Other Information
IR Spectrum:
Prominent absorptions at 3435, 1615, 1175, 844 and 832 cm-1, indicating OH, H2O, and AlOH. Also bands at 844 and 832 cm-1 due to AsO43-.
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 Esperanzaite
mindat.org URL:
https://www.mindat.org/min-6919.html
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References for Esperanzaite
Reference List:
Localities for Esperanzaite
Showing 1 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.
Mexico (TL) | |
| AmMin 85:263] +1 other reference |
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La Esperanza Mine, Francisco I. Madero, Pánuco de Coronado Municipality, Durango, Mexico