Anybody has heard of commodities investment (metal, nickel...etc)?

Yes, commodities is one of the 6 major asset classes.

Do you have a specific commodity you are looking to invest in? It is difficult to provide relevant information as commodity has a huge spectrum.

Commodities can range from Gold, Oil to our everyday needs such as food.
Depending on which commodity you choose to invest in, you will have to research and study it accordingly to find out relevant information.

For example, a drought on say cereal grain will impact the price of rice. That being said, commodities can be an important way to diversify a portfolio beyond traditional securities.

Do find out more on the specific type of commodities you wish to invest in, and risk factors that associate with it before investing.
Most people I know invest in Gold and Energy.