Yes - exactly! The RETAIL value (which is what an appriassal would reflect) may actually be high - that is, what it would cost to purchase the ring new. However, if you take it to a few reputable second hand jewellers/pawn shops, you will soon learn that the RESALE value of a ring is very, very low. Even lower when selling independently, like through Craig's List. The poor economy has flooded the market, not that resale was ever high, it's just worse now.
Financially, the smartest thing is to hang on to it, unless you just cannot see yourself, or any of your children, ever wearing or resetting it.