[skeeter (OP)]

My son is a big rock nut and is always on the hunt for new ones to add to his collection.  My wife found this today out behind the house.  It is a nice light pop bottle green color in outdoor lighting and is about the size of a silver dollar.  Thanks

[Bass]

White looks like quartz- conchoidal fracture is diagnostic.  If you can't scratch it with a pocketknife- then that confirms quartz.  Can't tell about the black material on the outside?

[Ophiolite]

The 'coating' ,material looks very much like pink feldspar (probably orthoclase), dark ferromagnesian mineral (probably biotite) and white quartz, which would make the main body - rightly identified as quartz by Bass - part of a quartz vein in a granite.