Eugsterite
A valid IMA mineral species
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About Eugsterite
Formula:
Na4Ca(SO4)3 · 2H2O
Colour:
Colorless
Hardness:
1 - 2
Crystal System:
Monoclinic
Name:
Named in 1981 by Lideke Vergouwen in honor of Hans-Peter Eugster (November 19, 1925–December 17, 1987), geochemist at Johns Hopkins University, Baltimore, Maryland, USA.
Unique Identifiers
Mindat ID:
1423
Long-form identifier:
mindat:1:1:1423:2
GUID
(UUID V4):
(UUID V4):
10e212bd-c57e-4b8a-b13d-c4e5875ba8bc
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
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r > v strong
Chemistry of Eugsterite
Mindat Formula:
Na4Ca(SO4)3 · 2H2O
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:
Reference:
Vergouwen, L. (1981) Eugsterite, a new salt mineral. American Mineralogist: 66: 632-636.
Synonyms of Eugsterite
Other Language Names for Eugsterite
German:Eugsterit
Spanish:Eugsterita
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 | Koktaite | (NH4)2Ca(SO4)2 · H2O |
7.CD.35 | Syngenite | K2Ca(SO4)2 · H2O |
7.CD.35 | Antofagastaite | Na2Ca(SO4)2 · 1.5H2O |
7.CD.40 | Gypsum | CaSO4 · 2H2O |
7.CD.45 | Bassanite | Ca(SO4) · 0.5H2O |
7.CD.45 | Chinleite-(Y) | NaY(SO4)2 · H2O |
7.CD.45 | Chinleite-(Nd) | NaNd(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.
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External Links:
Mineral Dealers:
References for Eugsterite
Reference List:
Localities for Eugsterite
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).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
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 et al. (South Lebanon) |
Peru | |
| Mees et al. (1991) |
Poland | |
| Kruszewski +1 other reference |
Russia | |
| Shablinskii et al. (2022) |
| Arkhipov et al. (2015) |
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 Province, Tarapacá, Chile