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Bobcookite
A valid IMA mineral species
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About Bobcookite
Robert B. Cook
Formula:
NaAl(UO2)2(SO4)4 · 18H2O
Colour:
Lime green to greenish-yellow
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
2.669 (Calculated)
Crystal System:
Triclinic
Name:
Named in honour of Dr. Robert B. “Bob” Cook (b. 1944), former distinguished professor and head of the Department of Geology and Geography at Auburn University, Auburn, Alabama.
Unique combination of elements. Stoichiometry and hydration level somewhat similar to that of the closely associated wetherillite.
In the structure there are (UO2)(SO4)2(H2O) chains (sheets of identical composition are found in wetherillite); the chains are connected by NaO4(H2O)2 octahedra thus forming layers; hydrogen bonds to insular Al(H2O)6 octahedra and isolated water groups stabilize the structure holding together the building elements. Composition of the coordination sphere in Na octahedra in wetherillite is different.
In the structure there are (UO2)(SO4)2(H2O) chains (sheets of identical composition are found in wetherillite); the chains are connected by NaO4(H2O)2 octahedra thus forming layers; hydrogen bonds to insular Al(H2O)6 octahedra and isolated water groups stabilize the structure holding together the building elements. Composition of the coordination sphere in Na octahedra in wetherillite is different.
Unique Identifiers
Mindat ID:
46167
Long-form identifier:
mindat:1:1:46167:8
IMA Classification of Bobcookite
Classification of Bobcookite
7.EB.
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
E : Uranyl sulfates
B : With medium-sized cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
E : Uranyl sulfates
B : With medium-sized cations
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 |
|---|---|---|
| Bbc | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. |
Blue Lizard Mine, Red Canyon Mining District, San Juan County, Utah, USA