The ring is absolutely beautiful, as is most of your work. So I wish I could help more than I can. Maybe my thoughts as I first looked at the seal will help somehow.

Long, long ago and far, far away I did a graduate paper on early Near Eastern cylinder (not stamp) seals. The main thing I was looking at then was the central hero figure (or Gilgamesh, or god, or goddess) flanked by two rampant beasts. So no help here. But I did look at a lot of seals. So many that my major professor made me a gift of one. And although it's been a long time, I have a sense that your seal IS Near Eastern, and perhaps pretty old:

No figures, no obvious cuneiform, so more probable from a temple? (as opposed to a business or merchant/trader. Or government official.) The crescent moon, the most prominant component of the design, is used to represent the moon god Nanna as long ago as the city-state of Ur. Pretty often it's shown with a star representing the sun god . . . looks like you might have star-like things in the bottom half of the seal. I'll see if a photo of an early crescent moon (and star) will post. If so, it's from about 2100 BCE.

And this is so far out on a limb I'm actually falling as we speak, so please forget it the minute you read it: in your seal we have the crescent moon, a star (the sun), a figure at the bottom that might be interpreted as a comet -- from what I can see -- and, on the left, the 7 circular depressions -- the Pleiades? Maybe I have a fever. I'll stop now.

Anyhow -- a way for you to go!

Thank you for your answer, arrived from the sky when already I was adjusting to the idea that no answers would come.
And a heart-warming answer too!(By the way, I hope you are feeling better).
What you say matches my own (unauthorized) opinion.
I purchased the seal as Sassanide, but after some research I noticed that: a)this kind of off-white, opaque agate was not common in Sassanide times b)the actual carving technique does not look Sassanide to me, c) last but not least, the carved symbols are Mesopotamian!
I agree with you: the Moon, the Sun, the Seven Pleiades and a comet (?) can be seen.Clearly a seal of religious or amuletic nature.
No need to say I feel elated.

And now I feel elated, too!

What a beautiful backstory for a beautiful ring.

(And yes, I'm better, thank you!)

Fall 1973 to Summer 2013, and beyond.
Back to India in 1973 -- was it October? -- after a few weeks visit to my parents in Barcelona, I was about to check in at the Rex Hotel in Bombay (a lot of people stopped there prior to heading for Goa and its Christmas Season parties) when I met my American friend Robert -- himself back from the States -- in his way down, my way up, the hotel's stairs.
We rejoiced at the meeting, and swap presents: mine was a nice turquoise from Iran, he presented me with a most beautiful antique ring: an oval rock crystal seal set in silver. On the seal, you could see the Crescent Moon, the Sun, and Seven Stars -- with a sentence in French all around them that read: JE LES INVOQUE TOUS POUR VOTRE BONHEUR (in English: May all favour your happiness).
Now, I fell into temptation. Such a fabulous seal, and set in silver? Wouldn't gold look better? So I went to my great friend and reputed Kashmiri jeweller Habibullah across the street and asked him to set the stone in gold, keeping of course the same con-voluted design.
The job was ready very soon, but as I was holding the new ring in my hand, the stone suddenly turned to dust. My consterned friend declared that it didn't endure the stress of setting. I was NOT elated.
Then, as I was going upstairs back to my hotel room, down was going Robert! I told him the story almost crying. He stared at me in consternation and said: "You may not believe it, but a few minutes ago I was about to take your turquoise to the silversmith, and it slipped from my hand, it fell to the ground, and BROKE".
I was horrified. I felt deeply hurt AND guilty.
I felt hurt and guilty for forty years.
I thought that perhaps the seal was unique, and I had been instrumental in its disappearance from Earth...I knew that some day I would have to make the seal and its spell revive. I had to delete this Karma!
So one night in 2013, unable to sleep, I felt time was ripe. But I also somehow understood that I had to not just replicate (this was of course not possible)but to reproduce the seal. My roots were not in French. Neither Spanish nor Catalan were (I guess)a choice. My command of Greek was not up to the task. So I voted for a Latin translation of the sentence that empowered the symbols.
I spent many sleepless nights consulting texts and dictionaries. Finally the motto TVAM IN SECVNDAM FORTVNAM OMNIA INVOCO was cast.
I looked for and purchased a clear crystal stone and had it carved. Once ready, I had the new seal set in the silver ring you can see here. Then I felt very, very good.
I have had not one, but several rings made to give suite to the Saga (thus putting back into the world the Sun/Moon/Stars-cum-motto ring), both in silver AND gold, both with a French or a Latin sentence, both with a con-voluted design or a plainer one.
The story is not finished yet, though:
One day, few months ago, my dazzled eyes see an ancient bead-seal for sale in the internet -- you know where in the internet, don't you?. And I purchase it for a triffle. And I feel that some pleroma has responded to my call, and gratifies me with an atonement. This seal is the really revived-one for me.
So, I have this beautiful off-white agate bead, this perhaps Sumerian seal, set in a con-voluted gold ring, the ring I am wearing now, as I write this probably too long story for you, ann -- and for all of you, my fellow Forumites.

Great story!
I too have a few "karma related" projects that must be finished. 40 years of guilt would be agony. SO glad you were able to relieve the burden.
Jeff

Nice to find a peer soul.
The guilt was mild ;-) but the suite has been delicious.

Love the story! Thanks for sharing!

I loved reading the whole story, imagining your feelings with every sentence. Thank you for sharing.

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.