Hey OD,
Is it marked as 14K? It looks alot like a blank coin planchet, but that wouldn't have a carat marking.
I found a blank silver dollar planchet, and it looks fairly similar. What part of Colorado are you in?
I know there was some private gold coin mintage going on in the mid 1800's, and that could be one
of thier blanks before stamping. Nice find!!!
HH Slabman