12 inches or so in length. Balanced feel. Had a thick cover of coquina she'll and rust which almost fell away after hitting with a rubber mallet. No visible markings other than the serrated pattern.
Shiv, also chiv, schiv, and shivvie, is a homemade knife-like weapon, especially one fashioned in prison. ... The derived verb, shiv means "to stab someone", a shivver being the criminal who attacks victims with a knife. A knife improvised in prison is also often called a shank.
Anything when you got time on your hands and want to hurt another while serving time. Items most would NEVER think of from a toothbrush to even a bar of soap believe it or not, and easily will kill a 6'5" 250lb man in a split second if done right.
Very interesting, anything from St. Augustine would have me guessing. Everyone and everything came through there as far as History is concerned. Interesting find!