What you have is a stamp seal, from the Sasanian Empire, the last pre-Islamic Persian empire established in 224 AD until 651 AD. This seal provides the full heavenly representation - the crescent moon, a five pointed sun, six stars representing the Pleiades, and a final independent star that could either represent Orion chasing the “seven sisters” or Aldebaran, the follower who follows the Pleiades through the night sky.

Such motifs constitute a set of shorthand documents on popular Sasanian culture. The heliacal (near dawn) rising of the Pleiades in spring in the northern hemisphere augured the opening of the seafaring and farming season: while its dawn autumnal setting marked the season's end.

The sun-moon standard display is a common motif of drahtn coin reverses in the third and fourth century AD so I would suggest a similar dating for your seal.