A 21st-century type coin set consists of one coin bearing each design produced by the United States Mint during the 21st century. That is an enormous number of coins (commemoratives, state quarters, ATB quarters, Sacagawea dollars, etc) in both circulated/uncirculated and proof finishes. We must not forget the material of the coins like clad, silver, gold, copper, platinum, etc.
The NGC type coin registry takes the one type coin for the series approach. Therefore that is only one State Quarter, one America the Beautiful Quarter, one Sacagawea Dollar and one Presidential Dollar required. They only consider coins that were meant for circulation, so no commemoratives and no gold or platinum coins.
I decided to collect a NGC-like 21st century type coin set but, looking always for perfection, my collection is made only by PF70 coins.
Let's show it, in order of value and year of each coin.
The twenty-fourth is a PF70 UC 2007-S "George Washington" Presidential Dollar.
The composition of the coin consists of a core of pure copper with an outer layer of manganese brass consisting of 77% copper, 12% zinc, 7% manganese and 4% nickel. It has a diameter of 26.5 mm and weight of 8.1 grams.
The info below comes from https://presidentialdollarguide.com/
"The Presidential $1 Coin Program honors the former Presidents of the United States of America on a series of golden colored dollar coins.
George Washington was the former General and Commander in Chief of the Continental Army. He was then unanimously elected as President. He served two terms as the 1st President of the United States from 1789-1797."
NGC graded 45,168 2007-S "George Washington" Dollar Proofs, with 10,153 as PF70 UC. 3,965,989 "George Washington" Dollar Proofs coins were minted in San Francisco in 2007.
I bought this coin in 2013 for $15.00 and today's price is around $35.00.
The obverse of the coin features a portrait of the President.
The reverse features a rendition of the Statue of Liberty that will be used for all Presidential Dollars.
Thank you for reading. Please comment, upvote, resteem and advise me.