This is a question even eBay does not make crystal clear because  Ebay's  vintage catagory includes the 1940's to 1980's.  I believe the term "vintage" is really an individual point of view, some saying at least 25 years old and others taking a harder line to say at least 50 years.      I guess if you were born in the 70's, you may consider the 1950's or 60's to be vintage. *  Just my opinion of course but vintage means several things, one of which is higher quality in a piece of jewery.  The jewelry was made better than it is today including gold jewelry sold in high end retail jewelry stores.    *  The diamonds and precious stones used 40's through  60's were better quality before the K-marts, Wal Marts and all of the rest of the discount houses got into the "fine" jewelry business.  I believe quality pieces should not have sad looking, off color gems but the Emeralds and Rubies sold frequently now are VERY cloudy and VERY poor quality.  Jewelry was sold in fine jewelry stores in the 1950's --60's and the prices were higher compared to those at the jewelry counters in the big box stores of today but the value, the appearance and especially the quality was so much better.  * In the Art Nouveau and Art Deco period rose gold was often used and the  1960's and  1970's showed white gold to be a favorite.  I worked at Kay Jewelers in the 1960's and if I remember correctly, we sold far more white gold rings than yellow gold. *  The mountings in this era were much more substantial in weight and most often American made. A thicker, heavier gold ring was much more the rule than the exception.