I'm thinking of buying a kettle for my drinking sessions

But I have some doubt about the kind. I've already read some posts about kettles, but I feel a bit confused :S
I would like to uderstand which of these kettles best suits japanese green tea brewing:
iron kettle
pottery kettle
purion kettle
I think that the iron kettle is the best, but I'm concerning about toxicity of high intake of iron. It's possible?
Lin's ceramic team answered me that pottery series and purion series both suits well, but how much well it could be the purion one? They didn't say me.
The pottery and purion also contain irons??
Considering the costs, the purion kettle is more or less the same of an iron kettle, the pottery one is cheaper.
Please help me decide

Gratefully,
Marco