Dustin is correct. Carbonia blue was a very similar process to the Carbona Blue used by Colt.The slight difference in spelling indicates that the Carbonia process was a proprietary process used by Smith & Wesson.

When you see an old bluing job that has areas where the blue looks as if it has flaked off rather than simply wore thin, that is a good indicator that you are looking at a Carbonia or Carbona blue.

A true sign of mental illness is any gun owner who would vote for an Anti-Gunner like Joe Biden.