What is the name of your state (only U.S. law)? Illinois
How valid is a patent on a jewelry box design? There is are larger company selling jewelry boxes, but there are a ton of Etsy sellers making the same style product without the logo branded now. How much of a strong hold or validity does a patent have on this type of item?
Design patents are issued for new, original, nonfunctional, ornamental designs. These patents cover visual elements only.
What you have with jewelry boxes is often a combination of design and utility patents - with a design patent protecting any ornamental elements and a utility patent protecting the functional characteristics.
In order to qualify for a patent, and stop others from making or using or marketing the creation, the creation must be novel and nonobvious. There might be no patent protecting what you see being sold on Etsy or it is also possible that licenses have been granted.
If there IS an infringement, it will be up to the patent holder to file a lawsuit against the infringer. If successful with his suit, the court can issue an injunction prohibiting future sales and a court can award damages - or the patent holder could work out a royalty agreement with the infringer to share profits.
It is also possible that the infringer could challenge the novelty and nonobviousness of the original creation and the patent could be found invalid.