A portable token and systems and methods for identification and authentication of the same are disclosed. The portable token may be utilized for a variety of purposes and uses a thin section of rock as a unique identifying element, which is extremely resistant to forgery or duplication. Identification and authorization of tokens is achieved by a system that uses optical examination of the microstructure and the refractive properties of crystalline minerals within the identifying element, by transmitted polarized light techniques. Comparison between stored reference data and acquired examination data is the basis for verifying authenticity. The naturally-occurring three-dimensional orientations of the optical axes of mineral crystals contribute to the identification information by their effects.