Question

which is the most useful form of iron

Answer 1

Answer:

It rusts easily, yet it is the most important of all metals.

Answer 2

Explanation:

In metallic state, iron is rare in the Earth's crust, limited mainly to deposition by meteorites. Iron ores, by contrast, are among the most abundant in the Earth's crust, although extracting usable metal from them requires kilns or furnaces capable of reaching 1,500 °C (2,730 °F) or higher, about 500 °C (900 °F) higher than what is enough to smelt copper. Humans started to master that process in Eurasia only about 2000 BCE , and the use of iron tools and weapons began to displace copper alloys, in some regions, only around 1200 BCE.