I was just pricing my fine amethyst stacks earlier and found a 10-stack to be listed at 4000 gold under the lense. On a whim, I then paid the temple 10 gold to appraise them as well, who told me a 10 stack was worth 1000 gold.
I then tested it again with a single fine sapphire; got a list price of around 4000 from the lense and 1000 from the temple. Fine Feldspar listed at 800 apiece under the lense and 200 apiece in the temple.
Invariably the temple appraises fine gems at 1/4 the value found by the pricing lens.