What materials are inflammable?

[TheMagicPirate]

If i needed to bulid a fireplace in a studio, with a small fire in it, what materials would i use?

Stone is not an option.
EDIT: Due to the logistics of building an actual stone fireplace in a studio and then taking it down. It would take too long to dry etc...

Thanks

EDIT : Ok so maybe fibreglass wasn't such a good idea

 

[TheMagicPirate]

snip

Gits

I knew what I meant. I think someone mentioned clay. I'm going to 'use' that.

Cheers guys