If you design is so unique, it may be regsitered as a design patent in the US by filing Design Patent Application to United State Patent and Trademark Office
If you get registered Design Patent, you can put your registration number on your product.
Even though it is not so unique, once you created your own work, your work (jeweries) are protected by Copy Right laws of the US. When you created without immitating someone else's work, it is automatically protected by Copyright laws.
If you like, you can put copyright mark on your products. Copyright mark is Circle and C XXXXX XXXXXke this one: ©.
You can use © year created this product and your name, you will see this example on this web page.
Good luck with your new venture!
I hope this information would be of your help, if so please accept my answer.