Grease strike?

[thing]

I got a half today,(sorry no camera phone) it appears to be a grease strike. the entire outer circumference of the coin, from under kenneys neck to the top of his hair is gone. It does not appear to be post mint damage, the coin has even wear. Any body know if it is worth anything, or has anyne encountered this before?

 

[bigscores]

Pictures are necessary.

It's also called struck through grease.