Eugsterite
A valid IMA mineral species
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About Eugsterite
Hans-Peter Eugster
Formula:
Na4Ca(SO4)3 · 2H2O
Colour:
Colorless
Hardness:
1 - 2
Crystal System:
Monoclinic
Name:
Named in 1981 by Lideke Vergouwen in honour of Hans-Peter Eugster (19 November 1925, Igis, Landquart, Grisons, Switzerland – 17 December 1987, Baltimore, Maryland, USA), geochemist at Johns Hopkins University, Baltimore, Maryland, USA.
Unique Identifiers
Mindat ID:
1423
Long-form identifier:
mindat:1:1:1423:2
IMA Classification of Eugsterite
Approved
First published:
1981
Type description reference:
Classification of Eugsterite
7.CD.25
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
D : With only large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
C : Sulfates (selenates, etc.) without additional anions, with H2O
D : With only large cations
29.4.2.1
29 : HYDRATED ACID AND NORMAL SULFATES
4 : AmBn(XO4)p·xH2O, with (m+n):p < 3:2 and > 1:1
29 : HYDRATED ACID AND NORMAL SULFATES
4 : AmBn(XO4)p·xH2O, with (m+n):p < 3:2 and > 1:1
25.4.6
25 : Sulphates
4 : Sulphates of Ca, Sr and Ba
25 : Sulphates
4 : Sulphates of Ca, Sr and Ba
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 |
|---|---|---|
| Egt | 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 Eugsterite
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
1 - 2 on Mohs scale
Comment:
Could not be mesured due to its sticky nature
Optical Data of Eugsterite
Type:
Biaxial
RI values:
nα = 1.492 nγ = 1.496
Max. Birefringence:
δ = 0.004
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.
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.
Surface Relief:
Moderate
Dispersion:
r > v strong
Chemistry of Eugsterite
Mindat Formula:
Na4Ca(SO4)3 · 2H2O
Element Weights:
Crystallography of Eugsterite
Crystal System:
Monoclinic
Morphology:
Thin fibers
Comment:
Monoclinic (?). Point Group: n.d.; Space Group: n.d. a = n.d. b = n.d. c = n.d. β = 116◦ Z = n.d.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.20 Å | (39) |
| 5.50 Å | (64) |
| 4.50 Å | (33) |
| 3.454 Å | (32) |
| 3.428 Å | (100) |
| 2.763 Å | (25) |
| 2.746 Å | (46) |
| 1.7126 Å | (61) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 25 : Evaporites (prebiotic) |
Geological Setting:
salt pans
Type Occurrence of Eugsterite
Co-Type Localities:
General Appearance of Type Material:
fibers have a thickness of 0.5-1.5 μm and they are up to 40 μm long
Place of Conservation of Type Material:
National Museum of Geology and Mineralogy, Hooglandse Kerkgracht 17, Leiden. the Netherlands
Geological Setting of Type Material:
Efforvescences in salt pans
Associated Minerals at Type Locality:
Synonyms of Eugsterite
Other Language Names for Eugsterite
Common Associates
Associated Minerals Based on Photo Data:
| 6 photos of Eugsterite associated with Sideronatrite | Na2Fe(SO4)2(OH) · 3H2O |
| 1 photo of Eugsterite associated with Gypsum | CaSO4 · 2H2O |
| 1 photo of Eugsterite associated with Halite | NaCl |
| 1 photo of Eugsterite associated with Mascagnite | (NH4)2SO4 |
| 1 photo of Eugsterite associated with Kaolinite | Al2(Si2O5)(OH)4 |
Related Minerals - Strunz-mindat Grouping
| 7.CD. | Argesite | (NH4)7Bi3Cl16 |
| 7.CD. | Campostriniite | (Bi3+,Na)3(NH4,K)2Na2(SO4)6 · H2O |
| 7.CD.05 | Matteuccite | NaHSO4 · H2O |
| 7.CD.10 | Mirabilite | Na2SO4 · 10H2O |
| 7.CD.15 | Lecontite | (NH4,K)NaSO4 · 2H2O |
| 7.CD.20 | Hydroglauberite | Na10Ca3(SO4)8 · 6H2O |
| 7.CD.30 | Görgeyite | K2Ca5(SO4)6 · H2O |
| 7.CD.35 | Syngenite | K2Ca(SO4)2 · H2O |
| 7.CD.35 | Antofagastaite | Na2Ca(SO4)2 · 1.5H2O |
| 7.CD.35 | Koktaite | (NH4)2Ca(SO4)2 · H2O |
| 7.CD.40 | Gypsum | CaSO4 · 2H2O |
| 7.CD.45 | Chinleite-(Y) | NaY(SO4)2 · H2O |
| 7.CD.45 | Bassanite | Ca(SO4) · 0.5H2O |
| 7.CD.45 | Chinleite-(Nd) | NaNd(SO4)2 · H2O |
| 7.CD.45 | Chinleite-(Ce) | NaCe(SO4)2(H2O) |
| 7.CD.50 | Zircosulfate | (Zr,Ti)(SO4)2 · 4H2O |
| 7.CD.55 | Schieffelinite | Pb10Te6+6O20(OH)14(SO4)(H2O)5 |
| 7.CD.60 | Montanite | Bi2(TeO6) · nH2O |
| 7.CD.65 | Omongwaite | Na2Ca5(SO4)6 · 3H2O |
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 Eugsterite
mindat.org URL:
https://www.mindat.org/min-1423.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
References for Eugsterite
Reference List:
Localities for Eugsterite
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 | |
| Ovejero Toledo et al. (2009) |
| Mineralogical Society of America - ... |
Austria | |
| Walter et al. (2016) |
Bolivia | |
| Bentz (2017) |
| Bentz (2017) | |
| Bentz (2017) | |
| Lizeca et al. (1999) |
Canada | |
| Kohut et al. (1993) | |
| Shang (2000) |
Chile | |
| SEM/EDAX analyzed - Hans Peter Bojar (main author of Ammineite) |
China | |
| Okada et al. (1994) |
| Okada et al. (1994) | |
| Okada et al. (1994) | |
| Okada et al. (1994) |
| Okada et al. (1994) |
| Okada et al. (1994) | |
| Okada et al. (1994) |
Germany | |
| in the collection of Christof Schäfer |
| Ingendahl (2016) |
| Hentschel (2014) +1 other reference |
| Färber (n.d.) |
Italy | |
| D'Angeli et al. (2018) |
| Gabriele Montagna |
Japan | |
| Kobayashi et al (2005) |
Kenya (TL) | |
| Vergouwen (1981) |
| Vergouwen (1981) |
| Vergouwen (1981) |
Lebanon | |
| Kruszewski (2019) |
Peru | |
| Mees et al. (1991) |
| Tyc et al. (2022) |
Poland | |
| Kruszewski et al. (2018) +1 other reference |
Russia | |
| Shablinskii et al. (2022) |
| Arkhipov et al. (2015) |
Slovakia | |
| Szakáll et al. (2014) |
Spain | |
| Vizcayno et al. (1995) |
| Vizcayno et al. (1995) | |
| Mees et al. (2011) |
Switzerland | |
| Musée Cantonale de Géologie de ... |
Turkey (TL) | |
| Vergouwen (1981) |
| Vergouwen (1981) | |
USA | |
| a spectroscopic exploration. Economic ... +1 other reference |
| Zielinski et al. (2001) |
| Buck et al. (2006) |
| Kampf et al. (2018) |
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Pabellón de Pica, Chanabaya, Iquique, Iquique Province, Tarapacá, Chile