Ron Guth:
This is a scarce Period One octagonal Quarter Dollar, one of only two such coins of this type (making it much more rare than the 1853 round Quarter Dollars). Breen & Gillio assigned this a rarity rating of Low Rarity 4, meaning "about 150 to 200 known." PCGS alone has certified over 100 of these, so the surviving population is probably well above 200. It is relatively easy to obtain in Mint State, with most examples appearing at the MS63 level. The finest known examples are a trio of PCGS MS65s.
In its intermediate die state, this variety develops a crudely shaped, circular defect around the second L of DOLLAR. The 8 of the date is always weak. Late die states show considerable, fine die rust on both sides.