Two rare and unique Washington Quarter errors were certified by PCGS recently. One is the third-known example of a two-tailed quarter that was probably issued between 1965 and 1967. The coin was graded PCGS MS62 and was bought by famous error specialist Fred Weinberg at the September 2017 Long Beach Coin, Currency, Stamp & Sports Collectible Expo. Many of the two-headed or two-tailed coins are man-made by cutting two coins in half and mating the matching parts. They produce a different sound when dropped on a hard surface.
A 1968-S Proof Quarter struck on a 90% silver planchet left over from 1964 was graded PCGS PR64 and bought by Mr. Weinberg at the September 2017 Long Beach Expo. The coin also comes with a July 1969 letter containing a spectrograph confirming it is a 90% silver / 10% copper composition. Some 1965 Silver Quarters exist but the offered coin is the only known post-1964 Proof Silver Quarter.