Vintage Turquoise Round ring

ON HOLD UNTIL FURTHER INFORMATION--Vintage Turquoise ring, purchased at an estate sale. I don't know the history behind it. Except the woman who owned it lived in Southern Ohio and owned her own business. She had to be in her late 80's when she passed. I'm unsure where this was originally purchased. It is very old and has been left in the condition it was found. (i.e. it would've up to the buyer to clean/ restore it. )