Coffinite
A valid IMA mineral species - grandfathered
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About Coffinite
Reuben Clare Coffin
Formula:
U(SiO4) · nH2O
Also given as (U4+,Th)(SiO4)1-x(OH)4x
Colour:
Black
Lustre:
Adamantine
Hardness:
5 - 6
Specific Gravity:
5.1
Crystal System:
Tetragonal
Member of:
Name:
Named in honor of Reuben Clare Coffin (29 October 1886, Longmont, Colorado, USA - 10 September 1972, Tulsa, Oklahoma, USA), geologist, for his outstanding geologic studies in southwestern Colorado. He worked as Chief Geologist of the Midwest Refining Company, later the Stanolind Oil and Gas company, and consultant to USGS.
This page provides mineralogical data about Coffinite.
Unique Identifiers
Mindat ID:
1106
Long-form identifier:
mindat:1:1:1106:4
GUID
(UUID V4):
(UUID V4):
cd6d9c3f-5b5e-4185-86d1-ca30ef5a6e43
IMA Classification of Coffinite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1955
Classification of Coffinite
9.AD.30
9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination
9 : SILICATES (Germanates)
A : Nesosilicates
D : Nesosilicates without additional anions; cations in [6] and/or greater coordination
51.5.2.4
51 : NESOSILICATES Insular SiO4 Groups Only
5 : Insular SiO4 Groups Only with cations in >[6] coordination
51 : NESOSILICATES Insular SiO4 Groups Only
5 : Insular SiO4 Groups Only with cations in >[6] coordination
14.16.2
14 : Silicates not Containing Aluminum
16 : Silicates of U
14 : Silicates not Containing Aluminum
16 : Silicates of U
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference |
|---|---|---|
| Cof | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Cof | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Coffinite
Adamantine
Transparency:
Opaque
Colour:
Black
Comment:
Transmitted light the smaller particles of coffinite-bearing material are pale brown to very dark brown on thin edges.
Hardness:
5 - 6 on Mohs scale
Tenacity:
Brittle
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
5.1 g/cm3 (Measured)
Optical Data of Coffinite
Type:
Uniaxial (+/-)
RI values:
nα = 1.730 - 1.750 nβ = 1.730 - 1.750
Max Birefringence:
δ = 1.730
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:
High
Pleochroism:
Visible
Comments:
Moderate; pale yellow-brown parallel to length, medium brown perdendicular to length.
Chemistry of Coffinite
Mindat Formula:
U(SiO4) · nH2O
Also given as (U4+,Th)(SiO4)1-x(OH)4x
Also given as (U4+,Th)(SiO4)1-x(OH)4x
Elements listed:
Common Impurities:
Al,Fe,As,V,Pb
Crystallography of Coffinite
Crystal System:
Tetragonal
Class (H-M):
4/mmm (4/m 2/m 2/m) - Ditetragonal Dipyramidal
Space Group:
I41/amd
Setting:
I41/amd
Cell Parameters:
a = 6.979 Å, c = 6.252 Å
Ratio:
a:c = 1 : 0.896
Unit Cell V:
304.51 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Extremely fine grained to massive. In colloform or botryoidal incrustations, radially fibrous.
Crystal Structure
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2x2x2 | 3x3x3 | 4x4x4
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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) |
|---|---|---|---|---|---|---|---|
| 0000083 | Coffinite | Fuchs L H, Gebert E (1958) X-ray studies of synthetic coffinite, thorite and uranothorites American Mineralogist 43 243-248 |  | 1958 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.48 Å | (100) |
| 4.64 Å | (95) |
| 2.636 Å | (95) |
| 1.803 Å | (70) |
| 2.789 Å | (45) |
| 1.849 Å | (35) |
| 1.738 Å | (35) |
Comments:
Synthetic. Natural material gives broad peaks or may be metamict.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 53 : Other minerals with taphonomic origins | <0.4 |
Geological Setting:
unoxidized uranium deposits
Type Occurrence of Coffinite
General Appearance of Type Material:
Fine grained. Often visually indistinguishable from uraninite.
Place of Conservation of Type Material:
The Natural History Museum, London, England, 1956,201; National Museum of Natural History, Washington, D.C., USA, 112646.
Geological Setting of Type Material:
Unoxidized uranium deposit. Replacements of organic material and as disseminations in sandstone.
Associated Minerals at Type Locality:
Reference:
Stieff, L.R., Stern, T.W., Sherwood, A.M. (1955) Preliminary description of coffinite - a new uranium mineral. Science: 121: 608-609.
Other Language Names for Coffinite
Varieties of Coffinite
| Zirconium- and Yttrium-bearing Coffinite | The ZrO2 and Y2O3 contents reach 13.8 and 3.4 wt.%, respectively (René, 2015). |
Relationship of Coffinite to other Species
Member of:
Other Members of this group:
| Hafnon | HfSiO4 | Tet. 4/mmm (4/m 2/m 2/m) : I41/amd |
| Reidite | ZrSiO4 | Tet. 4/m : I41/a |
| Stetindite-(Ce) | Ce(SiO4) | Tet. 4/mmm (4/m 2/m 2/m) : I41/amd |
| Thorite | Th(SiO4) | Tet. 4/mmm (4/m 2/m 2/m) : I41/amd |
| Zircon | Zr(SiO4) | Tet. 4/mmm (4/m 2/m 2/m) : I41/amd |
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
| 10 photos of Coffinite associated with Uraninite | UO2 |
| 4 photos of Coffinite associated with Eucairite | AgCuSe |
| 4 photos of Coffinite associated with Clausthalite | PbSe |
| 3 photos of Coffinite associated with Cleveite | UO2 |
| 3 photos of Coffinite associated with Sabatierite | TlCu6Se4 |
| 3 photos of Coffinite associated with Pitchblende | UO2 |
| 3 photos of Coffinite associated with Berzelianite | Cu2-xSe (x ≈ 0.12) |
| 3 photos of Coffinite associated with Pyrite | FeS2 |
| 2 photos of Coffinite associated with Tyuyamunite | Ca(UO2)2(VO4)2 · 5-8H2O |
| 2 photos of Coffinite associated with Fergusonite-(Y) | YNbO4 |
Related Minerals - Strunz-mindat Grouping
| 9.AD. | Adrianite | Ca12(Al4Mg3Si7)O32Cl6 |
| 9.AD.05 | Larnite | Ca2SiO4 |
| 9.AD.10 | Calcio-olivine | Ca2SiO4 |
| 9.AD.15 | Merwinite | Ca3Mg(SiO4)2 |
| 9.AD.20 | Bredigite | Ca7Mg(SiO4)4 |
| 9.AD.25 | Andradite | Ca3Fe3+2(SiO4)3 |
| 9.AD.25 | Almandine | Fe2+3Al2(SiO4)3 |
| 9.AD.25 | Calderite | Mn2+3Fe3+2(SiO4)3 |
| 9.AD.25 | Goldmanite | Ca3V3+2(SiO4)3 |
| 9.AD.25 | Grossular | Ca3Al2(SiO4)3 |
| 9.AD.25 | Henritermierite | Ca3Mn3+2(SiO4)2[◻(OH)4] |
| 9.AD.25 | Kimzeyite | Ca3Zr2(SiO4)(AlO4)2 |
| 9.AD.25 | Knorringite | Mg3Cr2(SiO4)3 |
| 9.AD.25 | Majorite | Mg3(MgSi)(SiO4)3 |
| 9.AD.25 | Morimotoite | Ca3(TiFe2+)(SiO4)3 |
| 9.AD.25 | Pyrope | Mg3Al2(SiO4)3 |
| 9.AD.25 | Schorlomite | Ca3Ti2(SiO4)(Fe3+O4)2 |
| 9.AD.25 | Spessartine | Mn2+3Al2(SiO4)3 |
| 9.AD.25 | Uvarovite | Ca3Cr2(SiO4)3 |
| 9.AD.25 | Wadalite | (Ca,Mg)6(Al,Fe3+)4((Si,Al)O4)3O4Cl3 |
| 9.AD.25 va | Hydrougrandite | (Ca,Mg,Fe2+)3(Fe3+,Al)2[(OH)4(SiO4)2] |
| 9.AD.25 va | Yamatoite | (Mn2+,Ca)3(V3+,Al)2(SiO4)3 |
| 9.AD.25 | Holtstamite | Ca3Al2(SiO4)2[◻(OH)4] |
| 9.AD.25 | Khoharite | Mg3Fe3+2(SiO4)3 |
| 9.AD.25 | Kerimasite | Ca3Zr2(SiO4)(Fe3+O4)2 |
| 9.AD.25 | Toturite | Ca3Sn2(SiO4)(Fe3+O4)2 |
| 9.AD.25 | Momoiite | Mn2+3V3+2(SiO4)3 |
| 9.AD.25 | Eringaite | Ca3Sc2(SiO4)3 |
| 9.AD.25 | Irinarassite | Ca3Sn2(SiO4)(AlO4)2 |
| 9.AD.25 | Menzerite-(Y) | (Y2Ca)Mg2(SiO4)3 |
| 9.AD.25 | Eltyubyuite | Ca12Fe3+10Si4O32Cl6 |
| 9.AD.25 | Blythite | Mn2+3Mn3+2[SiO4]3 |
| 9.AD.25 | Skiagite | Fe2+3Fe3+2[SiO4]3 |
| 9.AD.25 | Hutcheonite | Ca3Ti2(SiO4)(AlO4)2 |
| 9.AD.25 | UM1984-37-SiO:CrMn | Mn2+3Cr3+2(SiO4)3 |
| 9.AD.25 | Rubinite | Ca3Ti3+2Si3O12 |
| 9.AD.25 | Nikmelnikovite | Ca12(Fe2+Fe3+3Al3◻)[SiO4]6[◻(OH)4]5◻4 |
| 9.AD.25 | Midbarite | Ca3Mg2(V2Si)O12 |
| 9.AD.30 va | Auerlite | near Th(Si,P)O4 |
| 9.AD.30 | Hafnon | HfSiO4 |
| 9.AD.30 | Thorite | Th(SiO4) |
| 9.AD.30 | Zircon | Zr(SiO4) |
| 9.AD.30 | Stetindite-(Ce) | Ce(SiO4) |
| 9.AD.35 | Huttonite | ThSiO4 |
| 9.AD.35 | Tombarthite-(Y) | Y4(Si,H4)4O12-x(OH)4+2x |
| 9.AD.40 | Eulytine | Bi4(SiO4)3 |
| 9.AD.45 | Reidite | ZrSiO4 |
| 9.AD.55 | Jeffbenite | Mg3Al2Si3O12 |
Other Information
Notes:
Radioactive
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
Industrial Uses:
uranium ore
Internet Links for Coffinite
mindat.org URL:
https://www.mindat.org/min-1106.html
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References for Coffinite
Reference List:
STIEFF, L. R., STERN, T. W., SHERWOOD, A. M. (1955) Preliminary Description of Coffinite-- a New Uranium Mineral. Science, 121 (3147). 608-609 doi:10.1126/science.121.3147.608-a
STIEFF, L. R., STERN, T. W., SHERWOOD, A. M. (1955) Preliminary Description of Coffinite-- a New Uranium Mineral. Science, 121 (3147). 608-609 doi:10.1126/science.121.3147.608-a
Stieff, L. R., Stern, T. W., Sherwood, A. M. (1956) Coffinite, a uranous silicate with hydroxyl substitution: a new mineral. American Mineralogist, 41 (9-10) 675-688
Localities for Coffinite
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.
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Jackpile Mine, Laguna subdistrict, Cibola County, New Mexico, USA