The Mineral META-TORBERNITE


Meta-torbernite is a dehydration product of its close cousin, torbernite, hence the name. When the mineral torbernite loses water and converts to meta-torbernite, it usually undergoes pseudomorphism. A pseudomorph is generally an atom by atom replacement of one mineral's chemistry to form another mineral. The process leaves the crystal shape of the original mineral intact. Pseudomorph means false (pseudo) shape (morph). In this case, the conversion is not so dramatic since it involves only the loss of a few water molecules; therefore, a good pseudomorph is likely. The conversion is irreversible and ongoing, and all collection specimens of a certain age are almost certainly partially to totally converted. If accuracy is demanded, all torbernite collection pieces of a few years of age should be labeled as meta-torbenite.

The structure of meta-torbernite is composed of phosphate tetrahedrons linked to uranium-oxygen groups that form distorted octahedrons. The phosphates and uranium groups lie in sheets that are weakly held together by water molecules. This structure produces the tabular habit, the one perfect direction of cleavage, and the relative softness.

Remember, this is a radioactive mineral and should be stored away from other minerals that are affected by radioactivity and human exposure should always be limited.

PHYSICAL CHARACTERISTICS:

 

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