Estate jewelry is older, generally vintage,(under 100 years old) or antique, (over 100 years old). It is previously owned jewelry.
The best examples are prized for their beauty, rarity and the kind of hand work and detail not often seen in current jewelry designs
Today however, almost any jewelry that was previously owned is referred to as estate jewelry.
An estate jeweler is a Jeweler who specializes in this type of jewelry.
Carnegie Museum of Natural History shows many historic and antique examples of rare jewelry in their various exhibitions.