Off-Topic: Can you give me info about this Iranian coin?

I have this piece in my coin collection that needs identification. Can you help?

It is Iran/Persia silver. Weights 0.75 grams. Diameter is 16 mm.



Information from Wolfgang Schuster: Iran, Nasir al-Din Shah, Shahi Sefid, KM#889 (Y#7a), no date, Tehran mint.