Shading Practice

I've been needing to practice my shading and I recently got a new sketch pad with a different kind of paper (to me every sketch pad has different paper), so I wanted to test it out. I really like my new sketch pad! Oh, and I also got a new kneaded eraser, so of course I wanted to use charcoal because I haven't in like, forever. And what's better to use as shading practice than Loki's helmet?
This is just a quick concept sketch using graphite and black and white charcoal pencils. Sorry for the crappy pic... I used a phone and it was getting dark outside.

Art (c) Broadwinger
Loki and helmet design (c) Marvel
DO NOT USE.