Old jewelry is a popular item to collect, and some pieces are valuable. Old jewelry falls into two categories; costume and genuine. Costume is made from old rhinestones, plastics, silver plate and base metals (iron,nickel, lead, zinc or copper). Real jewelry is made from gemstones and precious metals (gold and silver).
Look for a stamp inside the band or a mark in print saying “solid gold” or “sterling.” After 1906, the addition of karat weight was added to jewelry, required by law. Look in guidebooks to study the types of jewelry designs from different centuries. A helpful guidebook is "Answers to Questions about Old Jewelry" 6th edition, by C. Jeanenne Bell, G.G., published by Krause Publications.
Look in guidebooks that have both pictures and a price guide to determine value. Old jewelry is easily found at garage sales, consignment stores, thrift stores, estate sales, and flea markets. Go to garage sales with plenty of singles, five dollar bills and change. Old jewelry in consignment stores is generally priced higher, because the commission is shared with store owner. Thrift stores are a great resource for old jewelry, and bargains can be found. Flea markets and estate sales are good places to look for old jewelry as well.
Learn how to identify what you find. Old costume jewelry is not stamped as gold or sterling. If made from base metals, it will appear tarnished, or worn. If made from nickel, it will have a distinctly old metal "smell." Old costume jewelry falls into distinct categories and sub-categories. For example, a sub-category of old costume jewelry would be plastic, which includes vintage Lucite, acetate or Bakelite brooches, rings, necklaces and bangles. Old plastic is identifiable from the patina, or inner surface appearance. When searching for old plastic jewelry, look for pieces that have no mold lines. That is an indication of an older piece. On newer pieces of plastic jewelry made since 1970, there are lines in the plastic indicating where the pieces are molded together.
Familiarize yourself with old jewelry manufacturer signatures, which were used to mark pieces of jewelry. To get an idea of signatures, check out the book "Collecting Rhinestone and Colored Jewelry," by Maryann Dolan, 4th edition. Look for quality costume jewelry makers when out searching for old jewelry, like Joseff of Hollywood.
Beware of imitation pieces. Genuine Joseff of Hollywood pieces have the company name within a rectangular, raised mark. Check out Morning Glory Antiques & Jewelry website (see Resources) to view vintage Joseff of Hollywood brooches and marks.
Don't collect severely damaged old costume jewelry. Old rhinestones can be replaced. However, any piece made from real gold or precious silver is worth collecting.