In 1849, the firm of Massachusetts and Californis had a variety of die trials and quasi-pattern coins struck on their behalf, presumably in preparation for a coining operation. Kagin-5C is one of the rarer and more unusual of these coins. When Don Kagin wrote the standard reference book on Pioneer Gold in 1981, he was unaware of this type. However, because this variety shares a reverse with his 5B, it has been recognized ever since as Kagin 5C.
We know of three demonstrably different examples. All three are lightly circulated and would grade in the EF to AU range. On one piece the S of DOLLARS has been obliterated. The mutilation was done, presumably, because the S is reversed on the actual coin and appears to be from a different font and size as the letters of DOLLAR. This may also be why the design was never completed or issued.
The last appearance of a Kagin 5C was in January 2015, when Heritage sold an NGC AU50 example for $9,400.