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Marchettiite
A valid IMA mineral species
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About Marchettiite
Formula:
C5H7N5O3
structural formula: (NH4)HO(CNNHC2C(OH)NC(OH)N)
Colour:
Pale pink to white
Lustre:
Dull
Hardness:
2 - 2½
Specific Gravity:
1.69 (Calculated)
Crystal System:
Triclinic
Name:
For Gianfranco Marchetti who collected the type material.
Natural ammonium hydrogen urate.
Known synthetic analogue.
This or a very similar compound may occur in ammonium urate stones (biogenic materials).
Known synthetic analogue.
This or a very similar compound may occur in ammonium urate stones (biogenic materials).
Unique Identifiers
Mindat ID:
52574
Long-form identifier:
mindat:1:1:52574:5
IMA Classification of Marchettiite
Classification of Marchettiite
10.AA.45
10 : ORGANIC COMPOUNDS
A : Salts of organic acids
A : Formates, Acetates, etc.
10 : ORGANIC COMPOUNDS
A : Salts of organic acids
A : Formates, Acetates, etc.
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 |
|---|---|---|
| Mht | 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 Marchettiite
Dull
Transparency:
Opaque
Colour:
Pale pink to white
Streak:
White
Hardness:
2 - 2½ on Mohs scale
Hardness Data:
Estimated
Tenacity:
Brittle
Cleavage:
Distinct/Good
Parallel to {001}
Parallel to {001}
Density:
1.69 g/cm3 (Calculated)
Comment:
Calculated using empirical formula and unit cell data
Optical Data of Marchettiite
Type:
Biaxial (-)
RI values:
nα = 1.503(3) nβ = 1.712(3) nγ = 1.740(1)
2V:
Measured: 40° (10)
Max. Birefringence:
δ = 0.237
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:
High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Chemistry of Marchettiite
Mindat Formula:
C5H7N5O3
structural formula: (NH4)HO(CNNHC2C(OH)NC(OH)N)
structural formula: (NH4)HO(CNNHC2C(OH)NC(OH)N)
Element Weights:
Elements listed:
Crystallography of Marchettiite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 3.6533(2) Å, b = 10.2046(7) Å, c = 10.5837(7) Å
α = 113.809(5)°, β = 91.313(8)°, γ = 92.44(1)°
α = 113.809(5)°, β = 91.313(8)°, γ = 92.44(1)°
Ratio:
a:b:c = 0.358 : 1 : 1.037
Unit Cell V:
360.312 ų
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.784 Å | (50) |
| 8.663 Å | (80) |
| 5.659 Å | (100) |
| 4.614 Å | (50) |
| 3.443 Å | (100) |
| 3.241 Å | (70) |
| 3.158 Å | (100) |
| 3.004 Å | (60) |
Comments:
From Type Description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 52 : Guano- and urine-derived minerals | <0.4 |
Type Occurrence of Marchettiite
General Appearance of Type Material:
Marchettiite occurs as aggregates of opaque pale pink to white, elongated, platy, prismatic crystals.
Place of Conservation of Type Material:
Type material is deposited in the collections of the Museum of Mineralogy, University of Padova, Via Giotto 1, I-35122, Padova, Italy, catalogue number MMP M17892
Geological Setting of Type Material:
Formed by low temperature (20-30ºC) alteration of organic material derived from bird or marmot excrement.
Associated Minerals at Type Locality:
Synonyms of Marchettiite
Other Language Names for Marchettiite
Dutch:Marchettiiet
German:Marchettiit
Related Minerals - Strunz-mindat Grouping
| 10.AA. | Henrysunite | Na2(C2H3O3)2(H2O) |
| 10.AA.05 | Formicaite | Ca(HCOO)2 |
| 10.AA.10 | Dashkovaite | Mg(HCOO)2 · 2H2O |
| 10.AA.20 | Acetamide | CH3CONH2 |
| 10.AA.25 | Calclacite | Ca(CH3COO)Cl · 5H2O |
| 10.AA.30 | Paceite | CaCu(CH3COO)4 · 6H2O |
| 10.AA.35 | Hoganite | Cu(CH3COO)2 · H2O |
| 10.AA.40 | Lianbinite | (NH4)(C2H3O3)(C2H4O3) |
| 10.AA.40 | Domitrovicite | Zn(C2H3O3)2 · 2H2O |
| 10.AA.40 | Puschridgeite | Mn(C2H3O3)2(H2O)2 |
| 10.AA.40 | Lazaraskeite | Cu(C2H3O3)2 |
| 10.AA.40 | Glecklerite | Na(C2H3O3) |
| 10.AA.40 | Jimkrieghite | Ca(C2H3O3)2 |
| 10.AA.40 | Stanevansite | Mg(C2H3O3)2 · 2H2O |
| 10.AA.40 | Rasmussenite | Ca(C2H3O3)2 · 3H2O |
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 Marchettiite
mindat.org URL:
https://www.mindat.org/min-52574.html
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Please feel free to link to this page.
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References for Marchettiite
Reference List:
Hålenius, U., Hatert, F., Pasero, M., Mills, S. J. (2017) New minerals and nomenclature modifications approved in 2017, CNMNC Newsletter No 40. Mineralogical Magazine, 81 (6) 1577-1581 doi:10.1180/minmag.2017.081.096
deepcarbon.net (n.d.) https://deepcarbon.net/feature/marchettiite-joins-new-carbon-mineral-roster-13
Guastoni, Alessandro, Nestola, Fabrizio, Zorzi, Federico, Lanza, Arianna, Ernst, Michelle, Gentile, Paolo, Andò, Sergio, Lorenzetti, Alessandra (2022) Marchettiite, (NH4)C5H3N4O3, a new organic mineral from Mount Cervandone, Devero Valley, Western–Central Alps, Italy. Mineralogical Magazine, 86 (6) 966-974 doi:10.1180/mgm.2022.97
Localities for Marchettiite
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.
Italy (TL) | |
| Hålenius et al. (2017) +1 other reference |
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Mount Cervandone, Monte Cervandone area, Devero Alp, Baceno, Verbano-Cusio-Ossola Province, Piedmont, Italy