Punchmark (6-armed Gandharan symbol with a dot between two of the arms) / blank. 9mm, 0.25 grams. Rare. Rajgor 579var.

A few dozen coins of this type appeared on the market in 2014. They seem to be from the later issues, a bit crude and struck in somewhat debased silver. The size is around 9mm, the weight of the specimens I got to examine range from 0.26 to 0.30 grams). 

Gandhara Janapada was one of the 16 Janapadas mentioned in the Buddhist chronicles. It was a subject of the Achaemenid Empire during the reign of Darius in the late 6th century BC, and was the birthplace of the first indian coins.