There are mines of chrome, mercury, cinnabar, argentiferous lead and rock salt.
These are made of alternate layers of soft wrought iron and chrome steel hardened by sudden cooling.
There are many other valuable ores - copper, iron, lead, zinc, antimony, chrome and manganese.
The yearly output of nickel and chrome is considerable, and these minerals, with cobalt, constitute the characteristic wealth of the island.
The hardness of the hardened chrome steel resists the burglar's drill, and the ductility of the wrought iron the blows of his sledge.