Horseman advancing right, holding a spear, no mintmark / Inscription in five lines "KNZ bVELIKIY VSEYA RUSY" ("Grand Duke of all Russia"). 15mmx11mm, 0.64 grams. Novgorod mint. Griszin #75; Russian Wire Coins #75.
This is a full kopeck (not a denga), weighing 0.60 grams. The coin was minted in Novgorod around 1540 when Ivan was still just a Grand Duke and not a Tsar.