Nickel is a really great metal. It is buried deep beneath the earth and it is thought that the lower levels of the earth are thick with it. This will mean tunnelling deeper will be difficult! Nickel is used for a variety of things. It is a good conductor of electricity and, most importantly, does not rust as easily as other metals. This is why Nickel composites make some of the best in the industry and are used to a great degree.
The human race discovered Nickel quite by accident. German copper miners were very annoyed to find it instead of the copper they actually wanted in the first place. To the German miners it was the work of the mischievous demon kupfernickel, hence why where we get the name.
An enterprising scientist Baron Axel Fredrik Cronstedt (actually Swedish and not German as you probably thought) used charcoal to heat some up and then found that it made a nice white metal and that it was extremely magnetic. He got rid of the kupfer part of its name as well.
Most Nickel is found in Canada, the result of a meteor strike so it is thought. There are growing mines in South Africa and Russia as well.