eBay. It was a cheap curiosity purchase, as I don't collect Indian coins, but it gives me something to post when people ask, "What's your smallest coin?"
Don't have a picture at the moment, but my smallest is a 2001 Liberia Washington $25 coin. only .73 grams but its .999 pure.
LESBOS, Mytilene. EL Hekte – Sixth Stater Circa 478-455 BC Diameter: 10 mm Weight: 2.48 grams Obverse: Ram’s head right Reverse: Incuse bull’s head right $380
I have one of those fanams I got in a lot of coins, but my smallest struck gold coin is a 4 Reales(then equivalent to a USA half dollar) from 1861 Guatemala. It should have roughly half the weight of a gold dollar.
Its the only gold coin I have, a gold Tremissis of Anastasius, emperor of the Eastern Roman Empire from 491 to 518 AD. It is 16 mm wide and 1.5 grams.