How do I get a price for my necklace

by Susan
(London )

In the early 80s I was given a broken double string necklace. It was given to me by an elderly gentleman in South Kensington. Who I did cleaning for. I just put it away and forgot about it. Last year I had it restrung. Iv done the home tests on your page and now believe that they are real. How do I find out how much they are worth