I have been running a small jewelry business (for funsies) for years. (I started it so I could buy my mom a huge diamond for her birthday at cost) Now I mainly sell to friends and family. My uncle has a full scale many-store business. My dad has a gun business, and I have a financial consulting business. I have been around business/jewelry my whole life, so that's where my advice comes from.
When you buy jewelry at a traditional retail store, the mark-up is unbelievable. 500% to start! (worse with diamonds)
Actual cash value of the jewelry is calculated by valuating 100% of the component value by weight. The current gold price is $1165 per ounce of pure 24k. That's $37.46 per gram. So take the weight of your gold in grams and multiply by $37.46. Then multiply by the concentration e.g. 10k is 41.7% pure, 14k is 58.3% pure, 18k is 75% pure. (k/24 or 14k/24k = percentage of purity) That will give you 100% of the gold value of your jewelry.
When jewelers buy gold, they usually pay from 50-65% of gold value. And pawn shops are just crooks!
With diamonds there's a completely different scale. There are 100 points in a carat so a half carat would be 50 points. Then you have to factor in cut, color, and clarity. Much more complicated. I can tell you that wholesale, a jeweler purchases a nice quality diamonds for way under $10 a point. (That's less than $1000 a carat for a near flawless diamond)
A word on appraisals.. they're for insurance and replacement cost purposes. They have nothing to do with the actual value of the piece. Selling to an individual you can expect to make 10-20% of the appraisal value, 20% for a large, high quality piece. Another thing about appraisals... they lie! I cannot tell you how many over-estimated appraisals I have seen. 1 carat total weight rings listed as 2+ carats on the appraisal. I'd say less than 5% of appraisals are factually accurate.
Buying or selling, you must educate yourself, then weigh and measure for yourself to really know what you're getting.
When I buy, I pay GV plus diamond value by a jewelers scale. I sell at just over component value. The smaller stuff I sell right at component value. Meaning if I have a ring that's 3grams of 14k plus a 10 point diamond, I sell it for 3grams of 14k, the diamonds are essentially free. I enjoy being fair and seeing people realize they can afford a nice piece for less than they imagined.
So now you have a better idea of what your rings are worth. If you'd like to PM me I'll give you a quote on your jewelry. Even if you don't sell to me, you have a good ballpark of where to start your pricing.