My guess would be that a large lamination broke off the bottom half of the obverse, and then the coin circulated normally for many years, yielding smooth surfaces and even wear. The thickness of the coin is slightly less around the laminated area; the reverse is completely normal. The obverse is somewhat reddish in color, as shown; date unknown. Price, $6 postpaid. Shipped only in the United States. Cash, check, or money order; no PayPal please.
