About.com explores Jewelry and answers the question: What is the difference between Antique, Vintage, and Estate jewelry? How can all “pre-owned” jewelry be estate but not all vintage?
About Style sums it up like this:
beginning of time – 1920’s : Antique
beginning of time – 1980’s : Vintage
beginning of time – 2010ish: Estate
So then technically you can have a piece from 1919 that is antique, vintage and estate, but a piece from the 90’s is not antique nor vintage although it is estate.
Estate usually means the item is simply pre-owned but usually made within the past 30 years or so because if a piece is older, it is usually titled as so, like vintage or antique- to indicate its age.
Vintage Jewelry is 20 or 30 years old or older, which means it includes Modern, Mid Century, Retro and Art Deco eras.
Antique jewelry is usually 100 years old or older. Beware of the added word “style” after these titles, since an “antique style” piece is something that is a replica of an older piece. Antique jewelry includes Art Deco, Edwardian, Belle Epoque, Art Nouveau, Victorian, Georgian and older pieces.