G'day David and many thanks for your query
The simple answer is 'MORE'
No I am NOT trying to be cute, but it's like saying you have a car – what's it worth?
I don't know the size, weight, color, cut, clarity and condition of the diamond, nor do I know the quality and metal and manufacture of the mount (ring).
So it's impossible for me to give you a quote anyway.
All I can say is – THE VALUE IS IN THE GEMSTONE.
While gold has gone up from the US$250 level to the current US$800 plus mark (3 times in value) that does NOT mean the diamond would have risen by the same amount.
It could be MORE!
You need to get it appraised – either by your local FRIENDLY jeweler – or if you have an old appraisal Certificate, you could do it yourself with our online appraisal system.
You can purchase that as a one off (US$19.95) or by becoming a Member of this site, you get three FREE appraisals every month.
Whatever you decide – you need to do it NOW!
If something happens and you do NOT have a current appraisal – your insurance may not cover you for any where near the real value of the item.
Hope that helps…