Hello everyone, I am new to the community and I thought this might be the right place to seek advice and guidance. I own a 4 carat, old European cut diamond that originates from late 19th century / early 20th century Russia. It was purchased in Belgrade, Serbia in the early 1960s by my father for my mother. I had it appraised by Gubelin in Zurich, Switzerland and they have estimated its market value (not including its vintage / historical character) at 14000 USD. I would like to know whether this appraisal fully appreciate the potential value of the solitaire. I will attache photographs of the item in question. Thank you in advance for any response.