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Uranophane

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Formula:
Ca(UO2)2[HSiO4]2 · 5H2O
System:
Monoclinic
Colour:
Light yellow, ...
Hardness:
2 - 3
Name:
Named in 1853 by Christian Friedrich Martin Websky for the chemical composition containing URANium plus Greek φαινερθαι "phainesthai", to appear, in allusion to the uncertainty of its composition as originally determined.
Dimorph of:

Classification of Uranophane

Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
9.AK.15

9 : SILICATES (Germanates)
A : Nesosilicates
K : Uranyl neso- and polysilicates
53.3.1.2

53 : NESOSILICATES Insular SiO4 Groups and Other Anions or Complex Cations
3 : Insular SiO4 Groups and Other Anions of Complex Cations with (UO2)
14.16.10

14 : Silicates not Containing Aluminum
16 : Silicates of U
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First Recorded Occurrence of Uranophane

Year of Discovery:
1853

Occurrences of Uranophane

Geological Setting:
Secondary mineral in uranium deposits and pegmatites.

Physical Properties of Uranophane

Vitreous, Greasy, Silky, Dull, Earthy
Diaphaneity (Transparency):
Transparent, Translucent
Comment:
Pearly on cleavage, waxy or dull when massive
Colour:
Light yellow, lemon-yellow, honey-yellow, straw-yellow, green-yellow
Hardness (Mohs):
2 - 3
Tenacity:
Brittle
Cleavage:
Perfect
on {100}
Density:
3.8 - 3.91 g/cm3 (Measured)    3.78 g/cm3 (Calculated)

Crystallography of Uranophane

Crystal System:
Monoclinic
Class (H-M):
2 - Sphenoidal
Space Group:
P21
Cell Parameters:
a = 15.85Å, b = 6.98Å, c = 6.64Å
β = 97.45°
Ratio:
a:b:c = 2.271 : 1 : 0.951
Unit Cell Volume:
V 728.40 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Composite needles, stellate aggregates, fibrous or felted crusts, massive.

Optical Data of Uranophane

Type:
Biaxial (-)
RI values:
nα = 1.643 nβ = 1.666 nγ = 1.669
2V:
Measured: 32° to 45°, Calculated: 38°
Max Birefringence:
δ = 0.026
Image shows birefringence interference colour range (at 30µm thickness) and does not take into account mineral colouration.
Surface Relief:
Moderate
Dispersion:
r < v strong
Pleochroism:
Weak
Comments:
X= colorless
Y= pale canary yellow
Z= canary yellow

Chemical Properties of Uranophane

Formula:
Ca(UO2)2[HSiO4]2 · 5H2O
Essential elements:
All elements listed in formula:

Relationship of Uranophane to other Species

Structurally related to group(s):
9.AK.05Soddyite(UO2)2SiO4 · 2H2O
9.AK.10CuprosklodowskiteCu(UO2)2[HSiO4]2 · 6H2O
9.AK.10Oursinite(Co,Mg)(UO2)2[HSiO4]2 · 6H2O
9.AK.10SklodowskiteMg(UO2)2[HSiO4]2 · 5H2O
9.AK.15Boltwoodite(K,Na)(UO2)[HSiO4] · 0.5H2O
9.AK.15KasolitePb(UO2)[SiO4] · H2O
9.AK.15Natroboltwoodite(H3O)(Na,K)UO2SiO4 · H2O
9.AK.15Uranophane-βCa(UO2)2(HSiO4)2 · 5H2O
9.AK.15Beta-Uranophane
9.AK.20SwamboiteUH6(UO2)6(SiO4)6 · 30H2O
9.AK.25HaiweeiteCa(UO2)2[Si5O12(OH)2] · 6H2O
9.AK.25MetahaiweeiteCa(UO2)2Si6O15 · nH2O
9.AK.25Ranquilite
9.AK.30WeeksiteK2(UO2)2(Si5O13) · 4H2O
9.AK.30CoutinhoiteThxBa(1-2x)(UO2)2Si5O13 · (H2O)1+y (0 < x < 0.5 and 0 < y < (2+x))
9.AK.35Ursilite(Mg,Ca)4(UO2)4(Si2O5)5.5(OH)5 · 13H2O
9.AK.35MagnioursiliteMg4(UO2)4(Si2O5)5(OH)6 · 20H2O
9.AK.35CalcioursiliteCa4(UO2)4(Si2O5)5(OH)6 · 15H2O
9.AK.40UranosiliteUO3 · 7SiO2
14.16.1UranosiliteUO3 · 7SiO2
14.16.2Coffinite(U4+,Th)(SiO4)1-x(OH)4x
14.16.3Soddyite(UO2)2SiO4 · 2H2O
14.16.4SwamboiteUH6(UO2)6(SiO4)6 · 30H2O
14.16.5WeeksiteK2(UO2)2(Si5O13) · 4H2O
14.16.6Boltwoodite(K,Na)(UO2)[HSiO4] · 0.5H2O
14.16.7Natroboltwoodite(H3O)(Na,K)UO2SiO4 · H2O
14.16.8CuprosklodowskiteCu(UO2)2[HSiO4]2 · 6H2O
14.16.9SklodowskiteMg(UO2)2[HSiO4]2 · 5H2O
14.16.11Uranophane-βCa(UO2)2(HSiO4)2 · 5H2O
14.16.12HaiweeiteCa(UO2)2[Si5O12(OH)2] · 6H2O
14.16.13MetahaiweeiteCa(UO2)2Si6O15 · nH2O
14.16.15Steacyite(◻,K)(Na,Ca)2(Th,U)[Si8O20]
14.16.16Ekanite(Ca,Fe2+,Pb)2(Th,U)[Si8O20]
14.16.17KasolitePb(UO2)[SiO4] · H2O
14.16.18OrlitePb3(UO2)3(Si2O7)2 · 6H2O
14.16.19Oursinite(Co,Mg)(UO2)2[HSiO4]2 · 6H2O

Other Names for Uranophane

Name in Other Languages:
Dutch:Uranofaan
Italian:Uranofano
Simplified Chinese:硅钙铀矿
Spanish:Lambertita
Traditional Chinese:矽鈣鈾礦

Other Information

Weakly green, usually not fluorescent when massive
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

References for Uranophane

Reference List:
Zeits. deutsche Geol.Ges. (1853), 5, 427.

American Mineralogist (1939): 24: 324-328.

Ginderow, D. (1988) Structure de l'uranophane alpha, Ca(UO2)2(SiO3OH)2.5H2O. Acta Crystallographica: C44: 421-424.

American Mineralogist (1986): 71: 1489-1493.

Burns, P.C. (2005) U 6+ minerals and inorganic compounds: insights into an expanded structural hierarchy of crystal structures. Canadian Mineralogist: 43: 1839-1894.

Internet Links for Uranophane

Specimens:
The following Uranophane specimens are currently listed for sale on minfind.com.

Localities for Uranophane

map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.
Mineral and/or Locality  
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