2017-S Effigy Mounds Proof

San Francisco opened the 2017 ATB proof slate with Richard Masters's Effigy Mounds design at 1,078,981 pieces, the figure matching the U.S. Mint Clad Proof Set sales total because the five 2017 quarters shipped as a packaged product. The reverse renders three of the Marching Bear effigy mounds at Effigy Mounds National Monument in northeastern Iowa, the bear-shaped earthworks built by the Effigy Moundbuilder cultural group between roughly 750 and 1400 CE along the Mississippi River bluffs. The composition shows the mounds from a slightly elevated perspective in serpentine procession, the only ATB design depicting prehistoric earthworks. The issue is the first of five 2017 releases, struck during the 225th-anniversary year of the U.S. Mint's founding by Congress on April 2, 1792.

Proof finish on the issue is the standard San Francisco style: mirrored fields struck from polished planchets against dies frosted in chemical baths before each press run. Cameo (CAM) and Deep Cameo (DCAM) are the contrast designations PCGS, the Professional Coin Grading Service, and NGC, the Numismatic Guaranty Company, apply on top of the numeric grade, with DCAM the default outcome rather than an upgrade tier. Grade distribution clusters at PR69-DCAM and PR70-DCAM with population counts in the thousands at the top. The diagnostic strike areas are the curved outlines of the bear-shaped mounds and the slightly raised ground texture between them, since the design relies on subtle contour-line relief rather than the figural detail that anchors most ATB reverses. The clad composition (75% copper-nickel over a pure copper core, 5.67 grams, 24.26 mm) matches every Washington quarter struck since 1965, so counterfeit risk is essentially nil at the issue's price point.

The issue trades in the lower price band typical of modern clad proofs and routes through year-set or design-set assembly. A raw certified PR69-DCAM example moves for a small premium over the cost of breaking up a sealed 2017 Clad Proof Set, and PR70-DCAM examples in NGC or PCGS holders sit at a modestly higher tier. The prehistoric-earthwork subject draws cross-disciplinary attention from Native American history, Iowa state, and archaeology-topical collectors, though the broader market treats it within the standard 2017 ATB proof price band. The 1.08 million print run is the lowest yet across the proof slate to that point and continues the proof-set sales decline that ran through the mid-decade. For the broader story of the ATB proof program and the series' production arc, see the Washington ATB series history.