Patina is a word thrown around a LOT in the vintage, thrift, and flea crowds. The true definition is a greenish or brown sheen found on metals due to oxidation; typically it happens due to age and wear. This bolo tie has some patina on it's large round medallion slide, and rather than clean it up, I left it, as I think it really adds to it's unique vibe.
This bolo tie is in good vintage condition! It has some wear consistent with age and patina as I mentioned, but will hold up looking classic for years to come.