take it into any jewelers and ask them for a apraisal first, or if you are going to sell the items on ebay find the exact weights of the gold and whether its 9, 18 or 24crt, the Cut, Clarity, Colour and Carat of the stone/s and then check ebay for similar weights to gauge your selling prices.

its a good idea to keyword search "scrap gold" on ebay to gauge the prices paid,here is a link to live trading gold prices per troy ounce:

http://www.taxfreegold.co.uk/goldpriceslive.html

deduct about a third of the current price per troy ounce and that will give you an idea of current ebay market value sold has a second hand item.

has for the inlaid diamond/s dependant on the four C's (see above) i would suggest you take them out and take them to a jewelers instead to sell, or have them reset in another peice that you do like has you wont get noware near what they are worth on ebay