Copyright law protects many different types of original artistic expressions that are original to the creator and fixed in a tangible form. Artistic pieces like earrings, necklaces, broaches, rings, and bracelets may be protected by copyright law if there are original creative elements that can be identified separately from the functional aspects of the piece of jewelry. 

So the clasp on the necklace may not be protected, but the original design of the part of the necklace that hangs around the neck may be protected. Any part of the jewelry piece that is functional is not protected by copyright law.

Jewelry designers who create original designs should consider obtaining copyright registrations for their original pieces to protect their work. Upon receiving a copyright application, a copyright examiner will review the design to determine if there was enough creativity or originality to warrant copyright protection.

For example, a basic design for gold hoop earrings will not be creative or original enough to warrant copyright protection. However, if the designer incorporated an original design into the gold hoop, that design may be protected if it is creative enough. The decision by the copyright examiner is very fact-intensive and dependent on whether or not the design has any original artistic elements. 

If you design original jewelry and want your work to be protected under copyright law so no one copies your original designs, you might want to talk to an intellectual property lawyer. The copyright application process is not very expensive and may be worth exploring.