They weren't like paper thin or anything; I'd say around as thick as a US dime, maybe just a tad thinner. And they had what looked like Indian script on them I think, but it was so small I could not fully tell.
"For as long as Belisarius lives, it is impossible for him to relinquish this city." - Roman general Belisarius, responding to a group of Gothic envoys, during the Gothic siege of Rome in 537 AD
Attributed coins in my collection so far - Roman: 238, Byzantine: 34, Post-Roman Germanic: 21