A glass tube semi-finished product or a hollow glass product manufactured from the glass tube semi-finished product is provided with a first marking with information regarding origin and manufacture of the glass tube semi-finished product and a second marking, the information of which second marking is linked to the information of the first marking, so as to enable a determination regarding authenticity of the glass tube semi-finished product, origin of the glass tube semi-finished product, and/or origin of an apparatus with which the first and/or second marking was generated on the glass tube semi-finished product. The first marking is a marking that is produced at temperatures above the transformation temperature of the glass in a counterfeit-proof manner. The combination of two markings provides a high level of protection against counterfeiting.
