This is a 2003 E-X Emerald Essentials Jersey card numbered to 250.
It's got everything going for it:
Silver foil lettering on the front
Game-worn jersey patch
Heavy glossy finish
It's a parallel card (there are similar cards numbered to 345, 175, 60 and 15)
It features a probably future Hall of Famer
And I only paid $3.99, including $2 shipping for it on eBay. That's nuts. Beckett lists the card at $18.
It's outer dimensions are the same as a regular card, but a lot of its been cut away.
The dark spots on the jersey piece are loose threads. My sewing expert daughter thinks it looks like something had been sewed on and thread hadn't been fully removed.