Mejillonesite
A valid IMA mineral species
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About Mejillonesite
North view of Cerro Mejillones
Cerro Mejillones, Mejillones peninsula, Mejillones, Antofagasta Province, Antofagasta, Chile
Cerro Mejillones, Mejillones peninsula, Mejillones, Antofagasta Province, Antofagasta, Chile
Formula:
[H5O2]+NaMg2(PO3OH)(PO4)(OH)
Colour:
Colorless
Lustre:
Vitreous
Hardness:
4
Specific Gravity:
2.36
Crystal System:
Orthorhombic
Name:
Named by Daniel Atencio, et al. in 2012 for the type locality of Cerro Mejillones.
This page provides mineralogical data about Mejillonesite.
Unique Identifiers
Mindat ID:
41151
Long-form identifier:
mindat:1:1:41151:2
GUID
(UUID V4):
(UUID V4):
cb83056d-8beb-4522-91d2-f3fcc88fbb24
IMA Classification of Mejillonesite
Classification of Mejillonesite
8.D0.
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
0 :
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
0 :
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 |
|---|---|---|
| Mej | 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 Mejillonesite
Vitreous
Transparency:
Transparent
Colour:
Colorless
Streak:
White
Hardness:
4 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Perfect on {100}, good on {010} and {001}.
Perfect on {100}, good on {010} and {001}.
Parting:
Not observed.
Fracture:
Step-Like
Density:
2.36(1) g/cm3 (Measured) 2.367 g/cm3 (Calculated)
Comment:
Measured in heavy liquids
Optical Data of Mejillonesite
Type:
Biaxial (-)
RI values:
nα = 1.507 nβ = 1.531
Max Birefringence:
δ = 1.507
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:
Low
Chemistry of Mejillonesite
Mindat Formula:
[H5O2]+NaMg2(PO3OH)(PO4)(OH)
Crystallography of Mejillonesite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Space Group:
Pbca
Setting:
Pbca
Cell Parameters:
a = 16.295(1) Å, b = 13.001(2) Å, c = 8.434(1) Å
Ratio:
a:b:c = 1.253 : 1 : 0.649
Unit Cell V:
1,786.75 ų (Calculated from Unit Cell)
Morphology:
The dominant form is the pinacoid {100}.
Prisms {hk0}, {h0l}, and {0kl} also observed.
Prisms {hk0}, {h0l}, and {0kl} also observed.
Twinning:
None observed.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.095 Å | (100) |
| 6.846 Å | (9) |
| 6.470 Å | (8) |
| 3.317 Å | (5) |
| 2.959 Å | (5) |
| 2.706 Å | (12) |
| 2.157 Å | (19) |
| 2.153 Å | (9) |
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] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| 52 : Guano- and urine-derived minerals | <0.4 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Mejillonesite
General Appearance of Type Material:
Prismatic and elongated thick tabular crystals up to 6 mm long, usually intergrown in radiating aggregates.
Place of Conservation of Type Material:
Museu de Geociências, Instituto de Geociências, Universidade de São Paulo, São Paulo (Brazil), catalogue no. DR712.
Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow (Russia), registration no. 4043/1.
Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow (Russia), registration no. 4043/1.
Geological Setting of Type Material:
Contact between a granite and what is now a fine-grained, completely altered siliceous layer at the base of a Pliocene (ca. 2.5 Ma) coastal bird guano deposit.
Associated Minerals at Type Locality:
Synonyms of Mejillonesite
Fluorescence of Mejillonesite
Short wave UV - None
Long wave UV - None
Long wave UV - None
Other Information
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 Mejillonesite
mindat.org URL:
https://www.mindat.org/min-41151.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
References for Mejillonesite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2011) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) Newsletter 8. Mineralogical Magazine, 75 (2) 289-294 doi:10.1180/minmag.2011.075.2.289
Atencio, D., Chukanov, N. V., Nestola, F., Witzke, T., Coutinho, J. M. V., Zadov, A. E., Contreira Filho, R. R., Farber, G. (2012) Mejillonesite, a new acid sodium, magnesium phosphate mineral, from Mejillones, Antofagasta, Chile. American Mineralogist, 97 (1) 19-25 doi:10.2138/am.2012.3867
Localities for Mejillonesite
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.
Chile (TL) | |
| |
Poland | |
|
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Cerro Mejillones, Mejillones peninsula, Mejillones, Antofagasta Province, Antofagasta, Chile