Beads this large and undamaged are exceedingly rare, this was excavated near Bagan.
The world would be a much bleaker place without agates. This bead makes me smile!
It may be considered a Chung dZi with the eye ground out of natural agate.
Approximately 112mm x 12 mm. (4 1/2″ by 1/3″)
100 BCE to 900 CE