2016-S Shawnee, Silver Proof

San Francisco opened the 2016 silver-proof slate with Susan Gamble's Shawnee design at 481,140 pieces, the figure matching the U.S. Mint's reported Silver Proof Set sales for 2016. The reverse renders Camel Rock, the layered sandstone hoodoo in southern Illinois that anchors Garden of the Gods inside Shawnee National Forest, with the surrounding hardwood canopy carried into the lower field. The silver composition is the 90% silver, 10% copper alloy the Mint had used for silver proof quarters since 1992, weighing 6.25 grams and carrying .1808 troy ounces of pure silver across a 24.26-millimeter planchet with reeded edge. Shawnee was the seventh national forest depicted in the program and the 31st of the 56-design ATB lineup. The 2016 Silver Proof Set print run fell roughly 7 percent below 2015 levels, continuing the modest contraction that ran through the program's middle years.

Authentication on the issue starts with weight. The 6.25-gram silver planchet against the 5.67-gram clad sister gives a calibrated jeweler's scale a half-gram spread to resolve, the cleanest non-destructive separation. The reeded edge reads as a uniform silver-gray band rather than the reddish copper-core line a clad piece shows at an angle. PCGS, the Professional Coin Grading Service, and NGC, the Numismatic Guaranty Company, label the slab insert with Silver or the S/Ag abbreviation alongside the numeric grade and a Cameo (CAM) or Deep Cameo (DCAM) contrast tier, where DCAM is the standard outcome rather than a premium upgrade because the working dies receive chemical etching before each press run. Strike diagnostics on the Camel Rock relief sit at the hoodoo's eroded ridge lines and the canopy texture in the lower field, both of which flatten under weak press pressure before any field issue shows.

The issue routes through Silver Proof Set assembly and ATB-design-set assembly rather than standalone pursuit, and trades at a modest premium over the silver-spot value carried by the 0.1808 ounce content. PR69-DCAM examples in PCGS or NGC holders move for a small step above the bullion floor; PR70-DCAM examples sit a tier higher with registry-set buyers driving the spread. The 481,140 print run against the 1,093,510 2016 clad proof figure gives the silver issue a roughly 2.3-to-1 scarcity ratio, though the broader half-million silver-set floor keeps the issue out of genuine scarcity territory. For the broader story of the ATB Silver Proof program and the series' production arc, see the Washington ATB series history.