Sunday, October 7, 2012

Lanthanide APEX Mineral

The next elements on the periodic table for my APEX mineral collection are the Lanthanides or "rare earth" elements.

Wikipedia Lanthanides

Lanthanum (La #57)   Lanthanum Minerals 
Cerium (Ce #58)   Cerium Minerals 
Praseodymium (Pr #59)   Praseodymium Minerals 
Neodymium (Nd #60)   Neodymium Minerals 
Promethium (Pr #61)   no Promethium minerals 
Samarium (Sm #62)   Samarium Minerals 
Europium (Eu #63)   Europium Minerals 
Gadolinium (Gd #64)   Gadolinium Minerals 
Terbium (Tb #65)   Terbium Minerals 
Dysprosium (Dy #66)   Dysprosium Minerals 
Holmium (Ho #67)   Holmium Minerals 
Erbium (Er #68)   Erbium Minerals 
Thulium (Tm #69)   Thulium Minerals 
Ytterbium (Yb #70)   Ytterbium Minerals 
Lutetium (Lu #71)   Lutetium Minerals 

Scandium (Sc #21) and Yttrium (Y #39) are often found in the same mineral deposits as the Lanthanides since they exhibit similar properties.  As a group these 17 elements are often called "rare earth elements".  They are actually quite common in small concentrations.  They are only "rare" because commercially viable deposits are rare.  

Light Lanthanide deposits are found in the Earths crust and are the most common available Lanthanides.  (Cerium, Lanthanum, Praseodymium, Samarium, Europium, and Gadolinium

Heavy Lanthanide deposits are found in the Earths mantle and are extremely rare.  (Dysprosium, Ytterbium, Erbium, and Gadolinium) 

The mineral collecting game gets different here.  The only APEX mineral I can collect will be Lanthanide enriched minerals with varying amounts of each element.  These minerals are often called "trash can" minerals since they can contain lots of different elements in unknown concentrations.
Bastnasite (X(CO3)F) is one possible APEX mineral choice for Lanthanides.   It will contain various Lanthanide elements for X.  

  • Bastnasite(Ce) (Ce(CO3)F) is the most common variant and contains about 45% Cerium and mostly light Lanthanides.

Monazite/Xenotime (X(PO4)) is another APEX mineral choice for Lanthanides.    It will contain various Lanthanide elements for X. 

  • Monazite(Ce) (Ce(PO4)) is one common variant with 45% Cerium and mostly light Lanthanides (Lanthanum, Praseodymium, Samarium, Europium, and Gadolinium)
  • Xenotime(Y) (Y(PO4)) is another common variant with 60% Yttrium and mostly heavy Lanthanides.

Euxenite (X2(O6)) is another possible APEX mineral choice for Lanthanides.    It will contain various Lanthanide elements for X.  

  • Euxenite (Ce) ((Y)(Nb)2(O6)) is the most common variant and contains Yttrium and Niobium.
These Lanthanide minerals are usually amphorous due to radiation damage from the Uranium and Thorium that are commonly included.

Promethium has no stable isotopes and therefore no minerals.  It is the least stable element of the first 82.
The Lanthanides are all silvery metals. The similarity in ionic radius between them makes it difficult to separate them from each other.
Lanthanides were not known historically.
Lanthanides are used in catalysts, glasses, phospors, and magnets.  The quantities consumed are relatively small in comparison to other elements.   Neodymium magnets, invented in the 1980s, are the strongest and most affordable type of rare-earth magnet. 
Lanthanides are not known to be necessary for any living organisms. They are typically low toxicity.

10/31/2013 - Update
Researchers have discovered a bacterium which needs rare earths to grow - in a hot spring. Methylacidiphilum fumariolicum requires lanthanum, cerium, praseodymium or neodymium as co-factor for the enzyme methanol dehydrogenase, with which the microbes produce their energy. The use of rare earths is possibly more widespread among bacteria than previously thought.

I often read about new science surprises.  What actually surprises me is that it surprises scientists and the public.  We aren't even close to figuring all this stuff out.  

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