Cyanide is used for actual color case hardening, because it is very high in carbon. Looks totally different from Turnbull, Colt or Uberti colors.
Uberti's case colors are attained through a chemically applied process.
Yes, Colt colors are bone charcoal. However, Uberti's case colors are so good these days, as I already said, I don't know why people pay the premium for Colt 2nd and 3rd generation percussion guns. The colors are very good and they're better made guns at a third the cost.
It's no Turnbull but pretty good for a $450 sixgun.
Even Colt pales next to Turnbull.