Choosing a Standard Setting or a Custom Setting

Mass-produced jewelry settings come in standard gem sizes. If a gem won’’t fit in a standard setting, you should have a setting custom made. This involves much more labor and, therefore, expense. When purchasing a gem or selecting a cut design, bear this in mind. Under some circumstances, the stone’s value makes cutting for maximum yield worthwhile. You can then pay for a custom setting later. However, in other circumstances, the gem’s value doesn’t justify the cost of a custom setting.

Do Gems Need to Match Standard Settings Precisely?

No, a gem doesn’t need to be the precise size of the jewelry setting. A skilled metalsmith can modify a standard setting to accommodate a variety of gem sizes. For example, any round gem can be put in a standard setting. For other shapes, metalsmiths must consider a variety of factors. As a general rule, gems under one carat can fall within 0.1 mm of the setting size. Over one carat, a 0.2 mm variance can usually be accommodated, sometimes more.

Estimating Weights for Gemstones

The carat weights given for standard gem sizes in the following chart apply to diamonds cut…