In the open-air gallery of the S.P.S. Museum, Srinagar, Kashmir, there is a 85-cm stone slab with an engraving of a six-cornered star inside a circle, with a small circle in its center. Similar symbols are found in different parts of Kashmir.
See: Bleazby. G.B; List of Coins & Medals in the S.P.S. Museum, Srinagar, Kashmir, pp. 1-3
This 85-cm stone slab seems antique but I couldn't find its dating.