[Cob] cob chimney

[Predrag Cvetkovic]

My friend and I will start our first cob work this Summer - a very small one
room, round house for guests, sitting with friends etc. We think about a
small fireplace too. It could be similar to this one:
http://www.cobworks.com/images/mexico08/final/7finalfireplace.jpg
but maybe with lower floor.
Does anyone have some experience about building cob fireplaces? I suppose we
should use firebricks as floor?

Is it a good idea to make a cob chimney too, or would be suggested something
other? Also, a question about the outer part of the chimney - out of the
roof - what it should be made of?
regards
Predrag