Postage stamps

Friedl forgery of the Red Mercury.
In general philatelic fakes and forgeries refers to labels that look like postage stamps. but aren't. Most have been produced to deceive or defraud. Learning to identify these can be a challenging branch of philately.
“ Stamps are legitimate if they are recognized internationally in practice, even if they are not recognized expressly, as by a treaty or international agreement. This is the same principle of international law that applies to the recognition of nation-states. A nation becomes a nation-state when the international community begins treating it as such."