Ikirombe cya oksidi ya etain: kiremereye, cy'ibara ry'umukara wijimye cyangwa umukara, gifite urumuri nk'urwa diyama. Ni cyo kirombe nyamukuru cya etain kandi gikoreshwa mu gukora buronze kuva hafi mu mwaka 3000 mbere ya Yezu. Mu mateka cyavanywe muri Cornwall, mu gace ka Iberiya no mu majyepfo y'uburasirazuba bwa Aziya.