Q. David Bowers (edited and updated by Mike Sherman): In 1866, the motto IN GOD WE TRUST was added to the reverse of the Liberty Seated quarter dollar, half dollar and silver dollar. The Liberty Seated obverse in combination with the eagle reverse with the added motto then continued in use through 1891, with the exception of some 1873 issues and all 1874 issues, which again displayed arrows at the date. Mintage was continuous at the Philadelphia mint, while San Francisco and Carson City produced coins in most years though 1878. The only New Orleans issues of the type is the 1891-O made during the last year the design was in use. There are a number of rarities within the span, with top honors being held by the 1873-CC (variety without arrows at date) of which just four or five specimens are known to exist out of an original mintage of 4,000.
The type collector will have no difficulty acquiring an example of one of the common dates of this type in nearly any grade desired. Keep in mind however, that quarters remain a bit tougher to get than either dimes or halves of the same period. Original mintages from 1879 through 1889 were extremely low (as were halves) as the mints were busy using their bullion supply and presses for striking the millions of silver dollars produced during this period.
-- Reprinted with permission from "United States Coins by Design Types - An Action Guide for the Collector and Investor" by Q. David Bowers