What This Coin Looks Like (Obverse, Reverse, Mint Mark Location, Special Features, etc.): Both the West Point and Philadelphia Mint produced 2015 bullion silver eagles (without mint mark). The combined mintage figure for both are 47000000. The last known mintage figure in 2017 for Philadelphia was only 79640 - making them very rare. There were no bullion silver eagles (no mint mark) minted in 2015.
Background: Due to strong demand for bullion Silver Eagles - the US Mint began minting these in San Francisco in 2011 to help supplement production and keep up with demand. People knew about them being minted in San Francisco because the Mint used to provide this information on the packaging. However in 2014 - they removed this information from their packaging. Because bullion silver eagles never have mint marks struck on their coins - it was impossible to determine which mint was producing the coins.
NGC began to notice small differences in the quality of the coins - particularly the West Point coins being of higher quality. West Point silver eagle coins are placed into tubes by robots - while Philadelphia and San Francisco coins are put in tubes manually. NGC also noticed differences in the serial number codes on the 500-coin "monster boxes" that silver eagles are distributed in. Due to a Freedom of Information Act request - the Mint released Mint identification information based on these serial numbers:
West Point - 2014-2017: Contains a 6 digit serial code starting with "1" - "2" or "3" - or a 5-digit code with a WP prefix.
Philadelphia: 2015: Contains 5-digit code staring with "1". 2016-2017: Contains 6 digit code starting with "5".
San Francisco: 2014: Contains red-colored strap on monster box. 2016-2017: Contains 6 digit code starting with "4".
Coin Value Chart: Typical Coin Prices, Values and Worth in USD based on Grade/Condition