Silver Eagle 25th Ann Set coin finishes?

I may be wrong here but it was always my understanding that burnished meant the planchets were buffed and/or polished and proof meant both the planchets and the fields of the dies used to strike the coins were polished and that was what created the mirrored field on the coin when struck multiple times at higher than normal pressure.

 

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For any high quality striking the blanks are polished...they are shiney and reflective but not mirror. The main finish on a coin comes from the die. There are some good vids on youtube showing this...http://www.pobjoy.com/usa/page.php?xPage=about_us.html has a video....perth mint has some. A planchet (blank) has to be polished to strike correctly. Otherwise it would be rough.

The US Mint doesn't produce or prepare precious metal blanks...they buy them from Perth Mint or Sunshine Mint. I was very suprised to find out that the US Mint did not roll or blank precious metal. They may roll and punch alloy blanks...not sure on that.

 

The ultimate finish impressed on the coin may be a combination of both blank prep and die prep. Given the enormous forces involved with multiple strikes by hardened dies on soft planchets it seems more likely that the die surface takes precedence. The burnishing process on the coins may mean that the coin will have few or fewer surface imperfections which are quite commonly seen in business strikes.

That said, I have 2 sets of the 25th Anniversary ASE. Finishes are almost the same for equivalents in each set. I suspect that some or most of the differences could be attributed to progressive die wear. TPG's seem to capitalize and mark coins (for example the UHR) as PL which could have been produced by worn dies but command huge premiums.