Urea
A valid IMA mineral species - grandfathered
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About Urea
Formula:
CO(NH2)2
Colour:
Colourless, pale yellow, pale brown
Specific Gravity:
1.33
Crystal System:
Tetragonal
Name:
The name is the common trivial name of this compound (derived from Greek "oura", urine). The systematic name is carbonic acid diamide.
Derived from bat guano and urine, stable only under very arid conditions.
Chemically identical to an organic compound (an amide) of the identical name.
Chemically identical to an organic compound (an amide) of the identical name.
Unique Identifiers
Mindat ID:
4117
Long-form identifier:
mindat:1:1:4117:7
Similar Names
| Urao | A synonym of Trona |
| Urre | A synonym of Native Gold |
IMA Classification of Urea
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
CO(N3-H2)2
Approval year:
1972
First published:
1973
Classification of Urea
10.CA.35
10 : ORGANIC COMPOUNDS
C : Miscellaneous Organic Minerals
A : Miscellaneous Organic Minerals
10 : ORGANIC COMPOUNDS
C : Miscellaneous Organic Minerals
A : Miscellaneous Organic Minerals
50.4.6.1
50 : ORGANIC COMPOUNDS
4 : Miscellaneous
50 : ORGANIC COMPOUNDS
4 : Miscellaneous
32.13
32 : Hydrocarbons, Resins and other Organic Compounds
32 : Hydrocarbons, Resins and other Organic Compounds
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 |
|---|---|---|
| Ur | 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 Urea
Transparency:
Translucent
Colour:
Colourless, pale yellow, pale brown
Streak:
Yellowish white
Density:
1.33 g/cm3 (Measured)
Comment:
Sink- float method in Nujol and α-bromonaphthalene.
Optical Data of Urea
Type:
Uniaxial (+)
RI values:
nω = 1.484 nε = 1.603
Max. Birefringence:
δ = 0.119
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
Chemistry of Urea
Mindat Formula:
CO(NH2)2
Element Weights:
Elements listed:
Crystallography of Urea
Crystal System:
Tetragonal
Class (H-M):
42m - Scalenohedral
Space Group:
P421m
Cell Parameters:
a = 5.646(1) Å, c = 4.701(1) Å
Ratio:
a:c = 1 : 0.833
Unit Cell V:
149.86 ų (Calculated from Unit Cell)
Z:
2
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) |
|---|---|---|---|---|---|---|---|
| 0020672 | Urea | Swaminathan S, Craven B M (1984) The crystal structure and molecular thermal motion of urea at 12, 60 and 123 K from neutron diffraction Acta Crystallographica B40 300-306 |  | 1984 | synthetic | 0 | 123 |
| 0020673 | Urea | Swaminathan S, Craven B M (1984) The crystal structure and molecular thermal motion of urea at 12, 60 and 123 K from neutron diffraction Acta Crystallographica B40 300-306 | | 1984 | synthetic | 0 | 60 |
| 0020674 | Urea | Swaminathan S, Craven B M (1984) The crystal structure and molecular thermal motion of urea at 12, 60 and 123 K from neutron diffraction Acta Crystallographica B40 300-306 | | 1984 | synthetic | 0 | 12 |
| 0010834 | Urea | Guth H, Heger G, Klein S, Treutmann W, Scheringer C (1980) Strukturverfeinerung von harnstoff mit neutronenbeugungsdaten bei 60, 123, 293 K und X-N- und X-X (1s2)-synthesen bei etwa 100 K Zeitschrift fur Kristallographie 153 237-254 |  | 1980 | 0 | 293 | |
| 0010833 | Urea | Guth H, Heger G, Klein S, Treutmann W, Scheringer C (1980) Strukturverfeinerung von harnstoff mit neutronenbeugungsdaten bei 60, 123, 293 K und X-N- und X-X (1s2)-synthesen bei etwa 100 K Zeitschrift fur Kristallographie 153 237-254 | | 1980 | 0 | 293 | |
| 0010832 | Urea | Guth H, Heger G, Klein S, Treutmann W, Scheringer C (1980) Strukturverfeinerung von harnstoff mit neutronenbeugungsdaten bei 60, 123, 293 K und X-N- und X-X (1s2)-synthesen bei etwa 100 K Zeitschrift fur Kristallographie 153 237-254 | | 1980 | 0 | 293 | |
| 0010831 | Urea | Guth H, Heger G, Klein S, Treutmann W, Scheringer C (1980) Strukturverfeinerung von harnstoff mit neutronenbeugungsdaten bei 60, 123, 293 K und X-N- und X-X (1s2)-synthesen bei etwa 100 K Zeitschrift fur Kristallographie 153 237-254 | | 1980 | 0 | 293 | |
| 0016652 | Urea | Worsham J, Levy H, Peterson S (1957) The positions of hydrogen atoms in urea by neutron diffraction _cod_database_code 1008776 Acta Crystallographica 10 319-323 | | 1957 | 0 | 293 |
CIF Raw Data - click here to close
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 49 : Oxic cellular biomineralization (see also #44) | <0.54 |
| 52 : Guano- and urine-derived minerals | <0.4 |
Type Occurrence of Urea
General Appearance of Type Material:
Damp incoherent mass of crystals.
Place of Conservation of Type Material:
Western Australia Museum, Perth, Australia, S4688.
Geological Setting of Type Material:
Cave guano from warm arid environment.
Associated Minerals at Type Locality:
Synonyms of Urea
Other Language Names for Urea
Related Minerals - Strunz-mindat Grouping
| 10.CA. | Allantoin | C4H6N4O3 |
| 10.CA. | Pabellóndepicaite | Cu2+2(N3C2H2)2(NH3)2(NO3)Cl · 2H2O |
| 10.CA. | Bojarite | Cu3(N3C2H2)3(OH)Cl2 · 6H2O |
| 10.CA. | Natrosulfatourea | Na2(SO4)[CO(NH2)2] |
| 10.CA. | 'Tholins' | (C,H,N) |
| 10.CA. | Fuchunite | Ba(C2H3O3)2(C2H4O3)2 |
| 10.CA.05 | Refikite | C20H32O2 |
| 10.CA.10 | Flagstaffite | C10H22O3 |
| 10.CA.15 | Hoelite | C14H8O2 |
| 10.CA.20 | Abelsonite | Ni(C31H32N4) |
| 10.CA.25 | Kladnoite | C6H4(CO)2NH |
| 10.CA.30 | 'Tinnunculite (of Chesnokov & Shcherbakova)' | C10H12N8O8 |
| 10.CA.30 | Guanine | C5H5N5O |
| 10.CA.40 | Uricite | C5H4N4O3 |
| 10.CA.45 | Chanabayaite | CuCl(N3C2H2)(NH3) · 0.25H2O |
| 10.CA.50 | Triazolite | NaCu2(N3C2H2)2(NH3)2Cl3 · 4H2O |
| 10.CA.55 | Ernstburkeite | Mg(CH3SO3)2 · 12H2O |
| 10.CA.60 | Joanneumite | Cu(C3N3O3H2)2(NH3)2 |
| 10.CA.65 | Tinnunculite | C5H4N4O3 · 2H2O |
| 10.CA.70 | 'Dopplerite' |
Other Information
Special Storage/
Display Requirements:
Display Requirements:
Stable only under very arid conditions.
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 Urea
mindat.org URL:
https://www.mindat.org/min-4117.html
Please feel free to link to this page.
Please feel free to link to this page.
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References for Urea
Reference List:
Worsham, J. E., Levy, H. A., Peterson, S. W. (1957) The positions of hydrogen atoms in urea by neutron diffraction. Acta Crystallographica, 10 (4) 319-323 doi:10.1107/s0365110x57000924
Pryor, A. W., Sanger, P. L. (1970) Collection and interpretation of neutron diffraction measurements on urea. Acta Crystallographica Section A, 26 (5) 543-558 doi:10.1107/s0567739470001390
Bridge, P. J. (1973) Urea, a new mineral, and neotype phosphammite from Western Australia. Mineralogical Magazine, 39 (303) 346-348 doi:10.1180/minmag.1973.039.303.11
Mullen, D., Hellner, E. (1978) A simple refinement of density distributions of bonding electrons. V. Bond electron density distribution in urea, CO(NH2)2, at 123 K. Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry, 34 (5) 1624-1627 doi:10.1107/s0567740878006172
Localities for Urea
Showing 8 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.
Australia (TL) | |
| Bridge (1973) |
Egypt | |
| Mahmoud et al. (2022) |
Iran | |
| Amin et al. (2022) |
Saudi Arabia | |
| Saudi Geological Survey Open-File ... +1 other reference |
United Arab Emirates | |
| Audra et al. (2017) |
USA | |
| A.R. Kampf |
| Kampf et al. (2019) +1 other reference |
| Jerry Baird collection |
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Kraftu cave, Divandarreh County, Kurdistan Province, Iran