Location:
Commonly found in caves, actually ONLY found in caves. Although if there was any logic in this world at all you would probably also be able to find it on the side of mountains and in riverbeds, but lets not think about that right now. ;)Descriptions:
Iron is a common metal that has high durability and strength. The ore form is completely useless unless it is melted down and forged. Although luckily for us, we can just find pre-forged and smithed iron in caves that is perfectly ready for crafting, because that's how nature works! 
Silver is uncommon metal that has medium durability and is quite strong. The metal deals a strong amount of damage towards monsters, so it is recommended a silver blade is carried when facing monstrous foes. Like Iron, it also requires forging to be of any use, but for whatever reasons we are able to find it pre-forged and crafting ready in caves!
Gold is a rare metal that has low durability and is very weak. It's only usefulness is its strong ability to conduct and project magic. Most strong wands and staffs use it as a base material. It is malleable, so casting it is very easy. Although, because magic? we can just craft it instantly, how realistic.
Aluminum is a common metal found that has medium durability and has medium strength. It also has the ability to conduct and project magic similar to gold, but not as strong. It is usually used as the base metal for any enchanted weapons (swords,spears,arrowheads). Aluminum in the real world is very rarely found in its pure form (actually rarer then diamonds in this condition). Although, same as all the other metals, we are able to find it pure and forged in caves. It seems that either we are extremely lucky, or someone is going around planting all this metal in the caves for us to find.
Brass is an alloy, but because there is someone/something that goes around and places it in caves for us (known as the Metal Santa), we can find it in them. It has a little lower durability and strength then Iron, but is a lot more malleable, making it easy to turn into special types of weapons. Instruments are also usually made from it because of the way it vibrates sound waves.Applications:
All metal found is useful for crafting an assortment of different types of weapons and tools, with varying strengths, durabilities, and magic conductivity.
For further information, see yourself out the door because metals don't make any since in this universe...
