G'day Bree2733 (sounds like someone from a sci-fi movie) - :-)
The answer is never that easy. It depends on certain circumstances that only YOU can answer.
Are you desperate for money? If so, the value goes as a 'Forced Sale' and could be as low as 5-10% of an appraisal.
If on the other hand you have time - Are you selling on auction?
This could see a price around 50%
Are you selling to the trade? Lower the value.
Selling to a friend or collector? Maybe as high as 70%
AND SO ON...
The golden rule is: "There ain't no such thing as a fixed price for anything..."
YOU - as a willing seller have to find a willing buyer. Between you is a price you will both agree on.
Remember that an appraisal (or insurance value) is simple the price an insurance company may have to pay for a 'Replacement of a similar article sometime in the future'
That's about all I can suggest.
You will find all this discussed on my website at the Jewelry Appraisal Center http://www.online-jewelry-appraisals.com
Hope that helps - Oh! and May the Force be with you :-)