The term finding is a generic word that encompasses all of the various items that make up a piece of jewelry. Sometimes the term is used to refer to clasps, or pin backs, or earring backs. At other times, the word refers to the blanks that make up a piece of jewelry, such as a holder for a cameo cabochon, or a piece of metal which is then cast into a brooch or pendant. (These latter pieces are more correctly termed blanks, since they are a holder but the actual piece is blank - waiting for a finish of some sort, whether it be engraving or some other metal technique.)
The term finding is very generic. A finding can be a small metal tag which would have been used for the designer marking, or a bezel mounting which holds a cabochon. It can be the clasp of a necklace or bracelet or the piece of metal which holds the rows of a multi strand jewelry design.
If you collect or resell vintage jewelry, a good knowledge of vintage jewelry findings is important because it can enable you to determine the age of a piece more accurately. For instance, the locking style of C clasp was invented in 1901, so any piece with this type of clasp would have to have been made after that date. Pierced earrings with a threaded screw back for the post were common about 1880, so if your earrings are this style, it might indicate that you have an older piece of jewelry.
Since all types of findings have been used in the production of jewelry for centuries, knowing the difference between the various types can be important. Modern jewelry findings are readily available and can be purchased from many retail stores and businesses online. But this is not the case with vintage findings.
Getting true vintage findings can be quite a daunting task. Many people who repair or remake jewelry will often buy up old collections of broken jewelry and search through them just to harvest just the findings, so that they will have them to use on their next repair or remodeling job. This will insure that the age of the piece is preserved.
Here are some examples of findings of the types that may have been used in vintage jewelry:
Findings photographs courtesy of B'sue Boutiques