New York Trademark Application Attorney.
Jewelry is a product that can encompass multiple types of intellectual property rights, but these rights may vary depending on the particular countries in which protection is sought. In the U.S., jewelry or portions thereof may be entitled to copyright, trademark, trade dress, and design patent protection. Copyright may protect the expressive/artistic component of the jewelry. But in the U.S., one does not need to register a copyright to be entitled to copyright protection. Registration...
I agree with my colleagues, but wish to add that you should inquire with your IP attorney about whether you are actually using the phrase as a trademark. Simply putting something on the front of a t-shirt may not always be considered sufficient to serve as a source-identifier for consumers. Disclaimer: The above statement is not intended as legal advice and is not the basis of an attorney-client relationship.
While I do not disagree with the other answers posted thus far, what you should do may depend on the reasons you feel you need to be covered in the other countries you listed. If you're only interested in the ability to stake a claim, you may be able to do so without trying to obtain trademark registrations (in some common law jurisdictions, you get some limited rights based on your commercial use of the mark even in the absence of a registration). If you don't expect to actually use the mark...