1831

The 1831 quarter eagle is the third year of the Reduced Diameter sub-type that William Kneass introduced in 1829, when Philadelphia retooled the denomination for the new close-collar press technology that produced uniform planchets and squared rims on every strike. Mint records put the year's delivery at 4,520 pieces, almost identical to the 4,540 produced in 1830 and consistent with the steady, low-thousands annual output that defined the sub-type from 1829 through its 1834 close. The portrait remained the Capped Head Left arrangement that John Reich had drawn for the 1821 redesign, but the planchet now measured 18.2 millimeters rather than the 18.5 millimeter standard used through 1827, and the close-collar process yielded sharper rim definition and more consistent strike quality than the earlier open-collar pieces could deliver.

Authentication should start with weight and metallurgy. A genuine 1831 weighs 4.37 grams on a calibrated scale and is composed of 0.9167 fine gold with the balance copper and silver, all per the pre-1834 Coinage Act standard. The reeded edge should be sharp and continuous with no parting seam visible under loupe magnification. Diameter is the second decisive diagnostic and should measure 18.2 millimeters across; an example reading 18.5 millimeters would belong to the earlier Large Diameter sub-type and indicate either a misattributed coin or, more often, a counterfeit struck from generic Capped Bust dies. Cast fakes turn up periodically and tend to give themselves away through pebbled field texture, soft relief in the star points and shield lines, and a faint seam along the edge where the mold halves met during casting.

For collectors building a Capped Bust quarter eagle date set, the 1831 is one of the more attainable Reduced Diameter years, though attainable here remains a relative term. Survival estimates from PCGS and NGC population data together suggest roughly seventy-five to one hundred and twenty-five examples across all grades, with most certified coins falling in the VF through AU range and Mint State pieces genuinely scarce when offered with original surfaces. A separate proof entry exists for 1831 and occupies an entirely different rarity tier. For circulation strikes, certified examples carry meaningful protection given the counterfeit history attached to early gold, and CAC-stickered pieces command strong premiums at auction. See the full Capped Bust Quarter Eagle series history.