Nice symbol on your Constantine II coin. Looks a bit more than a star to me, perhaps letters iota-chi,chi-iota, like the Lactantius account of Constantine's vision/dream. Lactantius died about 320. As we know, some examples look like just a star, no dot above. I'm posting a few photos of our star, the sun with rays and halo. Sometimes with the right conditions really nice rays and halos can be seen with the sun. Sun worship goes way back in human history with many cultures, Aztecs, Egyptians, Romans (Sol), etc. The nimbus, halo, was used as a sign of the divine, the heavenly. I'm now wondering if this symbol on these VIRTVS EXERCIT coins is not just any star but of our own sun. Constantine's vision was supposedly of Christ's sign appearing on or above the sun, so showing the sun's rays with a dot above may have been referring to this vision. It's fun to speculate. Blending the idea this symbol is both a star, our sun, and a Christian symbol portraying Constantine's vision, is worth consideration. This could explain the variations of the symbol from the mints. By the time Eusebius wrote Life Of Constantine, Constantine's vision had changed from the Lactantius iota-chi account to the chi-rho symbol. It seems the first account symbol didn't last long and was replaced by the true chi-rho.
